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143      <details id="toc" open><summary>Table of contents</summary><ul>
144<li><span class="stability_2"><a href="#tls_tls_ssl">TLS (SSL)</a></span>
145<ul>
146<li><a href="#tls_tls_ssl_concepts">TLS/SSL concepts</a>
147<ul>
148<li><a href="#tls_perfect_forward_secrecy">Perfect forward secrecy</a></li>
149<li><a href="#tls_alpn_and_sni">ALPN and SNI</a></li>
150<li><a href="#tls_pre_shared_keys">Pre-shared keys</a></li>
151<li><a href="#tls_client_initiated_renegotiation_attack_mitigation">Client-initiated renegotiation attack mitigation</a></li>
152<li><a href="#tls_session_resumption">Session resumption</a>
153<ul>
154<li><a href="#tls_session_identifiers">Session identifiers</a></li>
155<li><a href="#tls_session_tickets">Session tickets</a></li>
156</ul>
157</li>
158</ul>
159</li>
160<li><a href="#tls_modifying_the_default_tls_cipher_suite">Modifying the default TLS cipher suite</a></li>
161<li><span class="stability_0"><a href="#tls_class_tls_cryptostream">Class: <code>tls.CryptoStream</code></a></span>
162<ul>
163<li><a href="#tls_cryptostream_byteswritten"><code>cryptoStream.bytesWritten</code></a></li>
164</ul>
165</li>
166<li><span class="stability_0"><a href="#tls_class_tls_securepair">Class: <code>tls.SecurePair</code></a></span>
167<ul>
168<li><a href="#tls_event_secure">Event: <code>'secure'</code></a></li>
169</ul>
170</li>
171<li><a href="#tls_class_tls_server">Class: <code>tls.Server</code></a>
172<ul>
173<li><a href="#tls_event_connection">Event: <code>'connection'</code></a></li>
174<li><a href="#tls_event_keylog">Event: <code>'keylog'</code></a></li>
175<li><a href="#tls_event_newsession">Event: <code>'newSession'</code></a></li>
176<li><a href="#tls_event_ocsprequest">Event: <code>'OCSPRequest'</code></a></li>
177<li><a href="#tls_event_resumesession">Event: <code>'resumeSession'</code></a></li>
178<li><a href="#tls_event_secureconnection">Event: <code>'secureConnection'</code></a></li>
179<li><a href="#tls_event_tlsclienterror">Event: <code>'tlsClientError'</code></a></li>
180<li><a href="#tls_server_addcontext_hostname_context"><code>server.addContext(hostname, context)</code></a></li>
181<li><a href="#tls_server_address"><code>server.address()</code></a></li>
182<li><a href="#tls_server_close_callback"><code>server.close([callback])</code></a></li>
183<li><span class="stability_0"><a href="#tls_server_connections"><code>server.connections</code></a></span></li>
184<li><a href="#tls_server_getticketkeys"><code>server.getTicketKeys()</code></a></li>
185<li><a href="#tls_server_listen"><code>server.listen()</code></a></li>
186<li><a href="#tls_server_setsecurecontext_options"><code>server.setSecureContext(options)</code></a></li>
187<li><a href="#tls_server_setticketkeys_keys"><code>server.setTicketKeys(keys)</code></a></li>
188</ul>
189</li>
190<li><a href="#tls_class_tls_tlssocket">Class: <code>tls.TLSSocket</code></a>
191<ul>
192<li><a href="#tls_new_tls_tlssocket_socket_options"><code>new tls.TLSSocket(socket[, options])</code></a></li>
193<li><a href="#tls_event_keylog_1">Event: <code>'keylog'</code></a></li>
194<li><a href="#tls_event_ocspresponse">Event: <code>'OCSPResponse'</code></a></li>
195<li><a href="#tls_event_secureconnect">Event: <code>'secureConnect'</code></a></li>
196<li><a href="#tls_event_session">Event: <code>'session'</code></a></li>
197<li><a href="#tls_tlssocket_address"><code>tlsSocket.address()</code></a></li>
198<li><a href="#tls_tlssocket_authorizationerror"><code>tlsSocket.authorizationError</code></a></li>
199<li><a href="#tls_tlssocket_authorized"><code>tlsSocket.authorized</code></a></li>
200<li><a href="#tls_tlssocket_disablerenegotiation"><code>tlsSocket.disableRenegotiation()</code></a></li>
201<li><a href="#tls_tlssocket_enabletrace"><code>tlsSocket.enableTrace()</code></a></li>
202<li><a href="#tls_tlssocket_encrypted"><code>tlsSocket.encrypted</code></a></li>
203<li><a href="#tls_tlssocket_getcertificate"><code>tlsSocket.getCertificate()</code></a></li>
204<li><a href="#tls_tlssocket_getcipher"><code>tlsSocket.getCipher()</code></a></li>
205<li><a href="#tls_tlssocket_getephemeralkeyinfo"><code>tlsSocket.getEphemeralKeyInfo()</code></a></li>
206<li><a href="#tls_tlssocket_getfinished"><code>tlsSocket.getFinished()</code></a></li>
207<li><a href="#tls_tlssocket_getpeercertificate_detailed"><code>tlsSocket.getPeerCertificate([detailed])</code></a>
208<ul>
209<li><a href="#tls_certificate_object">Certificate object</a></li>
210</ul>
211</li>
212<li><a href="#tls_tlssocket_getpeerfinished"><code>tlsSocket.getPeerFinished()</code></a></li>
213<li><a href="#tls_tlssocket_getprotocol"><code>tlsSocket.getProtocol()</code></a></li>
214<li><a href="#tls_tlssocket_getsession"><code>tlsSocket.getSession()</code></a></li>
215<li><a href="#tls_tlssocket_getsharedsigalgs"><code>tlsSocket.getSharedSigalgs()</code></a></li>
216<li><a href="#tls_tlssocket_exportkeyingmaterial_length_label_context"><code>tlsSocket.exportKeyingMaterial(length, label[, context])</code></a></li>
217<li><a href="#tls_tlssocket_gettlsticket"><code>tlsSocket.getTLSTicket()</code></a></li>
218<li><a href="#tls_tlssocket_issessionreused"><code>tlsSocket.isSessionReused()</code></a></li>
219<li><a href="#tls_tlssocket_localaddress"><code>tlsSocket.localAddress</code></a></li>
220<li><a href="#tls_tlssocket_localport"><code>tlsSocket.localPort</code></a></li>
221<li><a href="#tls_tlssocket_remoteaddress"><code>tlsSocket.remoteAddress</code></a></li>
222<li><a href="#tls_tlssocket_remotefamily"><code>tlsSocket.remoteFamily</code></a></li>
223<li><a href="#tls_tlssocket_remoteport"><code>tlsSocket.remotePort</code></a></li>
224<li><a href="#tls_tlssocket_renegotiate_options_callback"><code>tlsSocket.renegotiate(options, callback)</code></a></li>
225<li><a href="#tls_tlssocket_setmaxsendfragment_size"><code>tlsSocket.setMaxSendFragment(size)</code></a></li>
226</ul>
227</li>
228<li><a href="#tls_tls_checkserveridentity_hostname_cert"><code>tls.checkServerIdentity(hostname, cert)</code></a></li>
229<li><a href="#tls_tls_connect_options_callback"><code>tls.connect(options[, callback])</code></a></li>
230<li><a href="#tls_tls_connect_path_options_callback"><code>tls.connect(path[, options][, callback])</code></a></li>
231<li><a href="#tls_tls_connect_port_host_options_callback"><code>tls.connect(port[, host][, options][, callback])</code></a></li>
232<li><a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext([options])</code></a></li>
233<li><span class="stability_0"><a href="#tls_tls_createsecurepair_context_isserver_requestcert_rejectunauthorized_options"><code>tls.createSecurePair([context][, isServer][, requestCert][, rejectUnauthorized][, options])</code></a></span></li>
234<li><a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer([options][, secureConnectionListener])</code></a></li>
235<li><a href="#tls_tls_getciphers"><code>tls.getCiphers()</code></a></li>
236<li><a href="#tls_tls_rootcertificates"><code>tls.rootCertificates</code></a></li>
237<li><a href="#tls_tls_default_ecdh_curve"><code>tls.DEFAULT_ECDH_CURVE</code></a></li>
238<li><a href="#tls_tls_default_max_version"><code>tls.DEFAULT_MAX_VERSION</code></a></li>
239<li><a href="#tls_tls_default_min_version"><code>tls.DEFAULT_MIN_VERSION</code></a></li>
240</ul>
241</li>
242</ul></details>
243
244      <div id="apicontent">
245        <h2>TLS (SSL)<span><a class="mark" href="#tls_tls_ssl" id="tls_tls_ssl">#</a></span></h2>
246
247<p></p><div class="api_stability api_stability_2"><a href="documentation.html#documentation_stability_index">Stability: 2</a> - Stable</div><p></p>
248<p><strong>Source Code:</strong> <a href="https://github.com/nodejs/node/blob/v14.19.1/lib/tls.js">lib/tls.js</a></p>
249<p>The <code>tls</code> module provides an implementation of the Transport Layer Security
250(TLS) and Secure Socket Layer (SSL) protocols that is built on top of OpenSSL.
251The module can be accessed using:</p>
252<pre><code class="language-js"><span class="hljs-keyword">const</span> tls = <span class="hljs-built_in">require</span>(<span class="hljs-string">'tls'</span>);</code></pre>
253<section><h3>TLS/SSL concepts<span><a class="mark" href="#tls_tls_ssl_concepts" id="tls_tls_ssl_concepts">#</a></span></h3>
254<p>The TLS/SSL is a public/private key infrastructure (PKI). For most common
255cases, each client and server must have a <em>private key</em>.</p>
256<p>Private keys can be generated in multiple ways. The example below illustrates
257use of the OpenSSL command-line interface to generate a 2048-bit RSA private
258key:</p>
259<pre><code class="language-bash">openssl genrsa -out ryans-key.pem 2048</code></pre>
260<p>With TLS/SSL, all servers (and some clients) must have a <em>certificate</em>.
261Certificates are <em>public keys</em> that correspond to a private key, and that are
262digitally signed either by a Certificate Authority or by the owner of the
263private key (such certificates are referred to as "self-signed"). The first
264step to obtaining a certificate is to create a <em>Certificate Signing Request</em>
265(CSR) file.</p>
266<p>The OpenSSL command-line interface can be used to generate a CSR for a private
267key:</p>
268<pre><code class="language-bash">openssl req -new -sha256 -key ryans-key.pem -out ryans-csr.pem</code></pre>
269<p>Once the CSR file is generated, it can either be sent to a Certificate
270Authority for signing or used to generate a self-signed certificate.</p>
271<p>Creating a self-signed certificate using the OpenSSL command-line interface
272is illustrated in the example below:</p>
273<pre><code class="language-bash">openssl x509 -req -<span class="hljs-keyword">in</span> ryans-csr.pem -signkey ryans-key.pem -out ryans-cert.pem</code></pre>
274<p>Once the certificate is generated, it can be used to generate a <code>.pfx</code> or
275<code>.p12</code> file:</p>
276<pre><code class="language-bash">openssl pkcs12 -<span class="hljs-built_in">export</span> -<span class="hljs-keyword">in</span> ryans-cert.pem -inkey ryans-key.pem \
277      -certfile ca-cert.pem -out ryans.pfx</code></pre>
278<p>Where:</p>
279<ul>
280<li><code>in</code>: is the signed certificate</li>
281<li><code>inkey</code>: is the associated private key</li>
282<li><code>certfile</code>: is a concatenation of all Certificate Authority (CA) certs into
283a single file, e.g. <code>cat ca1-cert.pem ca2-cert.pem > ca-cert.pem</code></li>
284</ul>
285<h4>Perfect forward secrecy<span><a class="mark" href="#tls_perfect_forward_secrecy" id="tls_perfect_forward_secrecy">#</a></span></h4>
286
287<p>The term <em><a href="https://en.wikipedia.org/wiki/Perfect_forward_secrecy">forward secrecy</a></em> or <em>perfect forward secrecy</em> describes a feature
288of key-agreement (i.e., key-exchange) methods. That is, the server and client
289keys are used to negotiate new temporary keys that are used specifically and
290only for the current communication session. Practically, this means that even
291if the server's private key is compromised, communication can only be decrypted
292by eavesdroppers if the attacker manages to obtain the key-pair specifically
293generated for the session.</p>
294<p>Perfect forward secrecy is achieved by randomly generating a key pair for
295key-agreement on every TLS/SSL handshake (in contrast to using the same key for
296all sessions). Methods implementing this technique are called "ephemeral".</p>
297<p>Currently two methods are commonly used to achieve perfect forward secrecy (note
298the character "E" appended to the traditional abbreviations):</p>
299<ul>
300<li><a href="https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange">DHE</a>: An ephemeral version of the Diffie-Hellman key-agreement protocol.</li>
301<li><a href="https://en.wikipedia.org/wiki/Elliptic_curve_Diffie%E2%80%93Hellman">ECDHE</a>: An ephemeral version of the Elliptic Curve Diffie-Hellman
302key-agreement protocol.</li>
303</ul>
304<p>Ephemeral methods may have some performance drawbacks, because key generation
305is expensive.</p>
306<p>To use perfect forward secrecy using <code>DHE</code> with the <code>tls</code> module, it is required
307to generate Diffie-Hellman parameters and specify them with the <code>dhparam</code>
308option to <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a>. The following illustrates the use of
309the OpenSSL command-line interface to generate such parameters:</p>
310<pre><code class="language-bash">openssl dhparam -outform PEM -out dhparam.pem 2048</code></pre>
311<p>If using perfect forward secrecy using <code>ECDHE</code>, Diffie-Hellman parameters are
312not required and a default ECDHE curve will be used. The <code>ecdhCurve</code> property
313can be used when creating a TLS Server to specify the list of names of supported
314curves to use, see <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a> for more info.</p>
315<p>Perfect forward secrecy was optional up to TLSv1.2, but it is not optional for
316TLSv1.3, because all TLSv1.3 cipher suites use ECDHE.</p>
317<h4>ALPN and SNI<span><a class="mark" href="#tls_alpn_and_sni" id="tls_alpn_and_sni">#</a></span></h4>
318
319<p>ALPN (Application-Layer Protocol Negotiation Extension) and
320SNI (Server Name Indication) are TLS handshake extensions:</p>
321<ul>
322<li>ALPN: Allows the use of one TLS server for multiple protocols (HTTP, HTTP/2)</li>
323<li>SNI: Allows the use of one TLS server for multiple hostnames with different
324SSL certificates.</li>
325</ul>
326<h4>Pre-shared keys<span><a class="mark" href="#tls_pre_shared_keys" id="tls_pre_shared_keys">#</a></span></h4>
327
328<p>TLS-PSK support is available as an alternative to normal certificate-based
329authentication. It uses a pre-shared key instead of certificates to
330authenticate a TLS connection, providing mutual authentication.
331TLS-PSK and public key infrastructure are not mutually exclusive. Clients and
332servers can accommodate both, choosing either of them during the normal cipher
333negotiation step.</p>
334<p>TLS-PSK is only a good choice where means exist to securely share a
335key with every connecting machine, so it does not replace PKI
336(Public Key Infrastructure) for the majority of TLS uses.
337The TLS-PSK implementation in OpenSSL has seen many security flaws in
338recent years, mostly because it is used only by a minority of applications.
339Please consider all alternative solutions before switching to PSK ciphers.
340Upon generating PSK it is of critical importance to use sufficient entropy as
341discussed in <a href="https://tools.ietf.org/html/rfc4086">RFC 4086</a>. Deriving a shared secret from a password or other
342low-entropy sources is not secure.</p>
343<p>PSK ciphers are disabled by default, and using TLS-PSK thus requires explicitly
344specifying a cipher suite with the <code>ciphers</code> option. The list of available
345ciphers can be retrieved via <code>openssl ciphers -v 'PSK'</code>. All TLS 1.3
346ciphers are eligible for PSK but currently only those that use SHA256 digest are
347supported they can be retrieved via <code>openssl ciphers -v -s -tls1_3 -psk</code>.</p>
348<p>According to the <a href="https://tools.ietf.org/html/rfc4279">RFC 4279</a>, PSK identities up to 128 bytes in length and
349PSKs up to 64 bytes in length must be supported. As of OpenSSL 1.1.0
350maximum identity size is 128 bytes, and maximum PSK length is 256 bytes.</p>
351<p>The current implementation doesn't support asynchronous PSK callbacks due to the
352limitations of the underlying OpenSSL API.</p>
353<h4>Client-initiated renegotiation attack mitigation<span><a class="mark" href="#tls_client_initiated_renegotiation_attack_mitigation" id="tls_client_initiated_renegotiation_attack_mitigation">#</a></span></h4>
354
355<p>The TLS protocol allows clients to renegotiate certain aspects of the TLS
356session. Unfortunately, session renegotiation requires a disproportionate amount
357of server-side resources, making it a potential vector for denial-of-service
358attacks.</p>
359<p>To mitigate the risk, renegotiation is limited to three times every ten minutes.
360An <code>'error'</code> event is emitted on the <a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a> instance when this
361threshold is exceeded. The limits are configurable:</p>
362<ul>
363<li><code>tls.CLIENT_RENEG_LIMIT</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Specifies the number of renegotiation
364requests. <strong>Default:</strong> <code>3</code>.</li>
365<li><code>tls.CLIENT_RENEG_WINDOW</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Specifies the time renegotiation window
366in seconds. <strong>Default:</strong> <code>600</code> (10 minutes).</li>
367</ul>
368<p>The default renegotiation limits should not be modified without a full
369understanding of the implications and risks.</p>
370<p>TLSv1.3 does not support renegotiation.</p>
371<h4>Session resumption<span><a class="mark" href="#tls_session_resumption" id="tls_session_resumption">#</a></span></h4>
372<p>Establishing a TLS session can be relatively slow. The process can be sped
373up by saving and later reusing the session state. There are several mechanisms
374to do so, discussed here from oldest to newest (and preferred).</p>
375<h5>Session identifiers<span><a class="mark" href="#tls_session_identifiers" id="tls_session_identifiers">#</a></span></h5>
376<p>Servers generate a unique ID for new connections and
377send it to the client. Clients and servers save the session state. When
378reconnecting, clients send the ID of their saved session state and if the server
379also has the state for that ID, it can agree to use it. Otherwise, the server
380will create a new session. See <a href="https://www.ietf.org/rfc/rfc2246.txt">RFC 2246</a> for more information, page 23 and
38130.</p>
382<p>Resumption using session identifiers is supported by most web browsers when
383making HTTPS requests.</p>
384<p>For Node.js, clients wait for the <a href="#tls_event_session"><code>'session'</code></a> event to get the session data,
385and provide the data to the <code>session</code> option of a subsequent <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a>
386to reuse the session. Servers must
387implement handlers for the <a href="#tls_event_newsession"><code>'newSession'</code></a> and <a href="#tls_event_resumesession"><code>'resumeSession'</code></a> events
388to save and restore the session data using the session ID as the lookup key to
389reuse sessions. To reuse sessions across load balancers or cluster workers,
390servers must use a shared session cache (such as Redis) in their session
391handlers.</p>
392<h5>Session tickets<span><a class="mark" href="#tls_session_tickets" id="tls_session_tickets">#</a></span></h5>
393<p>The servers encrypt the entire session state and send it
394to the client as a "ticket". When reconnecting, the state is sent to the server
395in the initial connection. This mechanism avoids the need for server-side
396session cache. If the server doesn't use the ticket, for any reason (failure
397to decrypt it, it's too old, etc.), it will create a new session and send a new
398ticket. See <a href="https://tools.ietf.org/html/rfc5077">RFC 5077</a> for more information.</p>
399<p>Resumption using session tickets is becoming commonly supported by many web
400browsers when making HTTPS requests.</p>
401<p>For Node.js, clients use the same APIs for resumption with session identifiers
402as for resumption with session tickets. For debugging, if
403<a href="#tls_tlssocket_gettlsticket"><code>tls.TLSSocket.getTLSTicket()</code></a> returns a value, the session data contains a
404ticket, otherwise it contains client-side session state.</p>
405<p>With TLSv1.3, be aware that multiple tickets may be sent by the server,
406resulting in multiple <code>'session'</code> events, see <a href="#tls_event_session"><code>'session'</code></a> for more
407information.</p>
408<p>Single process servers need no specific implementation to use session tickets.
409To use session tickets across server restarts or load balancers, servers must
410all have the same ticket keys. There are three 16-byte keys internally, but the
411tls API exposes them as a single 48-byte buffer for convenience.</p>
412<p>Its possible to get the ticket keys by calling <a href="#tls_server_getticketkeys"><code>server.getTicketKeys()</code></a> on
413one server instance and then distribute them, but it is more reasonable to
414securely generate 48 bytes of secure random data and set them with the
415<code>ticketKeys</code> option of <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a>. The keys should be regularly
416regenerated and server's keys can be reset with
417<a href="#tls_server_setticketkeys_keys"><code>server.setTicketKeys()</code></a>.</p>
418<p>Session ticket keys are cryptographic keys, and they <em><strong>must be stored
419securely</strong></em>. With TLS 1.2 and below, if they are compromised all sessions that
420used tickets encrypted with them can be decrypted. They should not be stored
421on disk, and they should be regenerated regularly.</p>
422<p>If clients advertise support for tickets, the server will send them. The
423server can disable tickets by supplying
424<code>require('constants').SSL_OP_NO_TICKET</code> in <code>secureOptions</code>.</p>
425<p>Both session identifiers and session tickets timeout, causing the server to
426create new sessions. The timeout can be configured with the <code>sessionTimeout</code>
427option of <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a>.</p>
428<p>For all the mechanisms, when resumption fails, servers will create new sessions.
429Since failing to resume the session does not cause TLS/HTTPS connection
430failures, it is easy to not notice unnecessarily poor TLS performance. The
431OpenSSL CLI can be used to verify that servers are resuming sessions. Use the
432<code>-reconnect</code> option to <code>openssl s_client</code>, for example:</p>
433<pre><code class="language-console"><span class="hljs-meta">$ </span><span class="language-bash">openssl s_client -connect localhost:443 -reconnect</span></code></pre>
434<p>Read through the debug output. The first connection should say "New", for
435example:</p>
436<pre><code class="language-text">New, TLSv1.2, Cipher is ECDHE-RSA-AES128-GCM-SHA256</code></pre>
437<p>Subsequent connections should say "Reused", for example:</p>
438<pre><code class="language-text">Reused, TLSv1.2, Cipher is ECDHE-RSA-AES128-GCM-SHA256</code></pre>
439</section><section><h3>Modifying the default TLS cipher suite<span><a class="mark" href="#tls_modifying_the_default_tls_cipher_suite" id="tls_modifying_the_default_tls_cipher_suite">#</a></span></h3>
440<p>Node.js is built with a default suite of enabled and disabled TLS ciphers. This
441default cipher list can be configured when building Node.js to allow
442distributions to provide their own default list.</p>
443<p>The following command can be used to show the default cipher suite:</p>
444<pre><code class="language-console">node -p crypto.constants.defaultCoreCipherList | tr ':' '\n'
445TLS_AES_256_GCM_SHA384
446TLS_CHACHA20_POLY1305_SHA256
447TLS_AES_128_GCM_SHA256
448ECDHE-RSA-AES128-GCM-SHA256
449ECDHE-ECDSA-AES128-GCM-SHA256
450ECDHE-RSA-AES256-GCM-SHA384
451ECDHE-ECDSA-AES256-GCM-SHA384
452DHE-RSA-AES128-GCM-SHA256
453ECDHE-RSA-AES128-SHA256
454DHE-RSA-AES128-SHA256
455ECDHE-RSA-AES256-SHA384
456DHE-RSA-AES256-SHA384
457ECDHE-RSA-AES256-SHA256
458DHE-RSA-AES256-SHA256
459HIGH
460!aNULL
461!eNULL
462!EXPORT
463!DES
464!RC4
465!MD5
466!PSK
467!SRP
468!CAMELLIA</code></pre>
469<p>This default can be replaced entirely using the <a href="cli.html#cli_tls_cipher_list_list"><code>--tls-cipher-list</code></a>
470command-line switch (directly, or via the <a href="cli.html#cli_node_options_options"><code>NODE_OPTIONS</code></a> environment
471variable). For instance, the following makes <code>ECDHE-RSA-AES128-GCM-SHA256:!RC4</code>
472the default TLS cipher suite:</p>
473<pre><code class="language-bash">node --tls-cipher-list=<span class="hljs-string">'ECDHE-RSA-AES128-GCM-SHA256:!RC4'</span> server.js
474
475<span class="hljs-built_in">export</span> NODE_OPTIONS=--tls-cipher-list=<span class="hljs-string">'ECDHE-RSA-AES128-GCM-SHA256:!RC4'</span>
476node server.js</code></pre>
477<p>The default can also be replaced on a per client or server basis using the
478<code>ciphers</code> option from <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a>, which is also available
479in <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a>, <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a>, and when creating new
480<a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a>s.</p>
481<p>The ciphers list can contain a mixture of TLSv1.3 cipher suite names, the ones
482that start with <code>'TLS_'</code>, and specifications for TLSv1.2 and below cipher
483suites. The TLSv1.2 ciphers support a legacy specification format, consult
484the OpenSSL <a href="https://www.openssl.org/docs/man1.1.1/man1/ciphers.html#CIPHER-LIST-FORMAT">cipher list format</a> documentation for details, but those
485specifications do <em>not</em> apply to TLSv1.3 ciphers. The TLSv1.3 suites can only
486be enabled by including their full name in the cipher list. They cannot, for
487example, be enabled or disabled by using the legacy TLSv1.2 <code>'EECDH'</code> or
488<code>'!EECDH'</code> specification.</p>
489<p>Despite the relative order of TLSv1.3 and TLSv1.2 cipher suites, the TLSv1.3
490protocol is significantly more secure than TLSv1.2, and will always be chosen
491over TLSv1.2 if the handshake indicates it is supported, and if any TLSv1.3
492cipher suites are enabled.</p>
493<p>The default cipher suite included within Node.js has been carefully
494selected to reflect current security best practices and risk mitigation.
495Changing the default cipher suite can have a significant impact on the security
496of an application. The <code>--tls-cipher-list</code> switch and <code>ciphers</code> option should by
497used only if absolutely necessary.</p>
498<p>The default cipher suite prefers GCM ciphers for <a href="https://www.chromium.org/Home/chromium-security/education/tls#TOC-Cipher-Suites">Chrome's 'modern
499cryptography' setting</a> and also prefers ECDHE and DHE ciphers for perfect
500forward secrecy, while offering <em>some</em> backward compatibility.</p>
501<p>128 bit AES is preferred over 192 and 256 bit AES in light of <a href="https://www.schneier.com/blog/archives/2009/07/another_new_aes.html">specific
502attacks affecting larger AES key sizes</a>.</p>
503<p>Old clients that rely on insecure and deprecated RC4 or DES-based ciphers
504(like Internet Explorer 6) cannot complete the handshaking process with
505the default configuration. If these clients <em>must</em> be supported, the
506<a href="https://wiki.mozilla.org/Security/Server_Side_TLS">TLS recommendations</a> may offer a compatible cipher suite. For more details
507on the format, see the OpenSSL <a href="https://www.openssl.org/docs/man1.1.1/man1/ciphers.html#CIPHER-LIST-FORMAT">cipher list format</a> documentation.</p>
508<p>There are only 5 TLSv1.3 cipher suites:</p>
509<ul>
510<li><code>'TLS_AES_256_GCM_SHA384'</code></li>
511<li><code>'TLS_CHACHA20_POLY1305_SHA256'</code></li>
512<li><code>'TLS_AES_128_GCM_SHA256'</code></li>
513<li><code>'TLS_AES_128_CCM_SHA256'</code></li>
514<li><code>'TLS_AES_128_CCM_8_SHA256'</code></li>
515</ul>
516<p>The first 3 are enabled by default. The last 2 <code>CCM</code>-based suites are supported
517by TLSv1.3 because they may be more performant on constrained systems, but they
518are not enabled by default since they offer less security.</p>
519</section><section><h3>Class: <code>tls.CryptoStream</code><span><a class="mark" href="#tls_class_tls_cryptostream" id="tls_class_tls_cryptostream">#</a></span></h3>
520<div class="api_metadata">
521<span>Added in: v0.3.4</span><span>Deprecated since: v0.11.3</span>
522</div>
523<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated: Use <a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a> instead.</div><p></p>
524<p>The <code>tls.CryptoStream</code> class represents a stream of encrypted data. This class
525is deprecated and should no longer be used.</p>
526<h4><code>cryptoStream.bytesWritten</code><span><a class="mark" href="#tls_cryptostream_byteswritten" id="tls_cryptostream_byteswritten">#</a></span></h4>
527<div class="api_metadata">
528<span>Added in: v0.3.4</span><span>Deprecated since: v0.11.3</span>
529</div>
530<p>The <code>cryptoStream.bytesWritten</code> property returns the total number of bytes
531written to the underlying socket <em>including</em> the bytes required for the
532implementation of the TLS protocol.</p>
533</section><section><h3>Class: <code>tls.SecurePair</code><span><a class="mark" href="#tls_class_tls_securepair" id="tls_class_tls_securepair">#</a></span></h3>
534<div class="api_metadata">
535<span>Added in: v0.3.2</span><span>Deprecated since: v0.11.3</span>
536</div>
537<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated: Use <a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a> instead.</div><p></p>
538<p>Returned by <a href="#tls_tls_createsecurepair_context_isserver_requestcert_rejectunauthorized_options"><code>tls.createSecurePair()</code></a>.</p>
539<h4>Event: <code>'secure'</code><span><a class="mark" href="#tls_event_secure" id="tls_event_secure">#</a></span></h4>
540<div class="api_metadata">
541<span>Added in: v0.3.2</span><span>Deprecated since: v0.11.3</span>
542</div>
543<p>The <code>'secure'</code> event is emitted by the <code>SecurePair</code> object once a secure
544connection has been established.</p>
545<p>As with checking for the server
546<a href="#tls_event_secureconnection"><code>'secureConnection'</code></a>
547event, <code>pair.cleartext.authorized</code> should be inspected to confirm whether the
548certificate used is properly authorized.</p>
549</section><section><h3>Class: <code>tls.Server</code><span><a class="mark" href="#tls_class_tls_server" id="tls_class_tls_server">#</a></span></h3>
550<div class="api_metadata">
551<span>Added in: v0.3.2</span>
552</div>
553<ul>
554<li>Extends: <a href="net.html#net_class_net_server" class="type">&#x3C;net.Server></a></li>
555</ul>
556<p>Accepts encrypted connections using TLS or SSL.</p>
557<h4>Event: <code>'connection'</code><span><a class="mark" href="#tls_event_connection" id="tls_event_connection">#</a></span></h4>
558<div class="api_metadata">
559<span>Added in: v0.3.2</span>
560</div>
561<ul>
562<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a></li>
563</ul>
564<p>This event is emitted when a new TCP stream is established, before the TLS
565handshake begins. <code>socket</code> is typically an object of type <a href="net.html#net_class_net_socket"><code>net.Socket</code></a>.
566Usually users will not want to access this event.</p>
567<p>This event can also be explicitly emitted by users to inject connections
568into the TLS server. In that case, any <a href="stream.html#stream_class_stream_duplex"><code>Duplex</code></a> stream can be passed.</p>
569<h4>Event: <code>'keylog'</code><span><a class="mark" href="#tls_event_keylog" id="tls_event_keylog">#</a></span></h4>
570<div class="api_metadata">
571<span>Added in: v12.3.0, v10.20.0</span>
572</div>
573<ul>
574<li><code>line</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> Line of ASCII text, in NSS <code>SSLKEYLOGFILE</code> format.</li>
575<li><code>tlsSocket</code> <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a> The <code>tls.TLSSocket</code> instance on which it was
576generated.</li>
577</ul>
578<p>The <code>keylog</code> event is emitted when key material is generated or received by
579a connection to this server (typically before handshake has completed, but not
580necessarily). This keying material can be stored for debugging, as it allows
581captured TLS traffic to be decrypted. It may be emitted multiple times for
582each socket.</p>
583<p>A typical use case is to append received lines to a common text file, which
584is later used by software (such as Wireshark) to decrypt the traffic:</p>
585<pre><code class="language-js"><span class="hljs-keyword">const</span> logFile = fs.<span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'/tmp/ssl-keys.log'</span>, { <span class="hljs-attr">flags</span>: <span class="hljs-string">'a'</span> });
586<span class="hljs-comment">// ...</span>
587server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'keylog'</span>, <span class="hljs-function">(<span class="hljs-params">line, tlsSocket</span>) =></span> {
588  <span class="hljs-keyword">if</span> (tlsSocket.<span class="hljs-property">remoteAddress</span> !== <span class="hljs-string">'...'</span>)
589    <span class="hljs-keyword">return</span>; <span class="hljs-comment">// Only log keys for a particular IP</span>
590  logFile.<span class="hljs-title function_">write</span>(line);
591});</code></pre>
592<h4>Event: <code>'newSession'</code><span><a class="mark" href="#tls_event_newsession" id="tls_event_newsession">#</a></span></h4>
593<div class="api_metadata">
594<details class="changelog"><summary>History</summary>
595<table>
596<tbody><tr><th>Version</th><th>Changes</th></tr>
597<tr><td>v0.11.12</td>
598<td><p>The <code>callback</code> argument is now supported.</p></td></tr>
599<tr><td>v0.9.2</td>
600<td><p><span>Added in: v0.9.2</span></p></td></tr>
601</tbody></table>
602</details>
603</div>
604<p>The <code>'newSession'</code> event is emitted upon creation of a new TLS session. This may
605be used to store sessions in external storage. The data should be provided to
606the <a href="#tls_event_resumesession"><code>'resumeSession'</code></a> callback.</p>
607<p>The listener callback is passed three arguments when called:</p>
608<ul>
609<li><code>sessionId</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The TLS session identifier</li>
610<li><code>sessionData</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The TLS session data</li>
611<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> A callback function taking no arguments that must be
612invoked in order for data to be sent or received over the secure connection.</li>
613</ul>
614<p>Listening for this event will have an effect only on connections established
615after the addition of the event listener.</p>
616<h4>Event: <code>'OCSPRequest'</code><span><a class="mark" href="#tls_event_ocsprequest" id="tls_event_ocsprequest">#</a></span></h4>
617<div class="api_metadata">
618<span>Added in: v0.11.13</span>
619</div>
620<p>The <code>'OCSPRequest'</code> event is emitted when the client sends a certificate status
621request. The listener callback is passed three arguments when called:</p>
622<ul>
623<li><code>certificate</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The server certificate</li>
624<li><code>issuer</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The issuer's certificate</li>
625<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> A callback function that must be invoked to provide
626the results of the OCSP request.</li>
627</ul>
628<p>The server's current certificate can be parsed to obtain the OCSP URL
629and certificate ID; after obtaining an OCSP response, <code>callback(null, resp)</code> is
630then invoked, where <code>resp</code> is a <code>Buffer</code> instance containing the OCSP response.
631Both <code>certificate</code> and <code>issuer</code> are <code>Buffer</code> DER-representations of the
632primary and issuer's certificates. These can be used to obtain the OCSP
633certificate ID and OCSP endpoint URL.</p>
634<p>Alternatively, <code>callback(null, null)</code> may be called, indicating that there was
635no OCSP response.</p>
636<p>Calling <code>callback(err)</code> will result in a <code>socket.destroy(err)</code> call.</p>
637<p>The typical flow of an OCSP Request is as follows:</p>
638<ol>
639<li>Client connects to the server and sends an <code>'OCSPRequest'</code> (via the status
640info extension in ClientHello).</li>
641<li>Server receives the request and emits the <code>'OCSPRequest'</code> event, calling the
642listener if registered.</li>
643<li>Server extracts the OCSP URL from either the <code>certificate</code> or <code>issuer</code> and
644performs an <a href="https://en.wikipedia.org/wiki/OCSP_stapling">OCSP request</a> to the CA.</li>
645<li>Server receives <code>'OCSPResponse'</code> from the CA and sends it back to the client
646via the <code>callback</code> argument</li>
647<li>Client validates the response and either destroys the socket or performs a
648handshake.</li>
649</ol>
650<p>The <code>issuer</code> can be <code>null</code> if the certificate is either self-signed or the
651issuer is not in the root certificates list. (An issuer may be provided
652via the <code>ca</code> option when establishing the TLS connection.)</p>
653<p>Listening for this event will have an effect only on connections established
654after the addition of the event listener.</p>
655<p>An npm module like <a href="https://www.npmjs.com/package/asn1.js">asn1.js</a> may be used to parse the certificates.</p>
656<h4>Event: <code>'resumeSession'</code><span><a class="mark" href="#tls_event_resumesession" id="tls_event_resumesession">#</a></span></h4>
657<div class="api_metadata">
658<span>Added in: v0.9.2</span>
659</div>
660<p>The <code>'resumeSession'</code> event is emitted when the client requests to resume a
661previous TLS session. The listener callback is passed two arguments when
662called:</p>
663<ul>
664<li><code>sessionId</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The TLS session identifier</li>
665<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> A callback function to be called when the prior session
666has been recovered: <code>callback([err[, sessionData]])</code>
667<ul>
668<li><code>err</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a></li>
669<li><code>sessionData</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
670</ul>
671</li>
672</ul>
673<p>The event listener should perform a lookup in external storage for the
674<code>sessionData</code> saved by the <a href="#tls_event_newsession"><code>'newSession'</code></a> event handler using the given
675<code>sessionId</code>. If found, call <code>callback(null, sessionData)</code> to resume the session.
676If not found, the session cannot be resumed. <code>callback()</code> must be called
677without <code>sessionData</code> so that the handshake can continue and a new session can
678be created. It is possible to call <code>callback(err)</code> to terminate the incoming
679connection and destroy the socket.</p>
680<p>Listening for this event will have an effect only on connections established
681after the addition of the event listener.</p>
682<p>The following illustrates resuming a TLS session:</p>
683<pre><code class="language-js"><span class="hljs-keyword">const</span> tlsSessionStore = {};
684server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'newSession'</span>, <span class="hljs-function">(<span class="hljs-params">id, data, cb</span>) =></span> {
685  tlsSessionStore[id.<span class="hljs-title function_">toString</span>(<span class="hljs-string">'hex'</span>)] = data;
686  <span class="hljs-title function_">cb</span>();
687});
688server.<span class="hljs-title function_">on</span>(<span class="hljs-string">'resumeSession'</span>, <span class="hljs-function">(<span class="hljs-params">id, cb</span>) =></span> {
689  <span class="hljs-title function_">cb</span>(<span class="hljs-literal">null</span>, tlsSessionStore[id.<span class="hljs-title function_">toString</span>(<span class="hljs-string">'hex'</span>)] || <span class="hljs-literal">null</span>);
690});</code></pre>
691<h4>Event: <code>'secureConnection'</code><span><a class="mark" href="#tls_event_secureconnection" id="tls_event_secureconnection">#</a></span></h4>
692<div class="api_metadata">
693<span>Added in: v0.3.2</span>
694</div>
695<p>The <code>'secureConnection'</code> event is emitted after the handshaking process for a
696new connection has successfully completed. The listener callback is passed a
697single argument when called:</p>
698<ul>
699<li><code>tlsSocket</code> <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a> The established TLS socket.</li>
700</ul>
701<p>The <code>tlsSocket.authorized</code> property is a <code>boolean</code> indicating whether the
702client has been verified by one of the supplied Certificate Authorities for the
703server. If <code>tlsSocket.authorized</code> is <code>false</code>, then <code>socket.authorizationError</code>
704is set to describe how authorization failed. Depending on the settings
705of the TLS server, unauthorized connections may still be accepted.</p>
706<p>The <code>tlsSocket.alpnProtocol</code> property is a string that contains the selected
707ALPN protocol. When ALPN has no selected protocol, <code>tlsSocket.alpnProtocol</code>
708equals <code>false</code>.</p>
709<p>The <code>tlsSocket.servername</code> property is a string containing the server name
710requested via SNI.</p>
711<h4>Event: <code>'tlsClientError'</code><span><a class="mark" href="#tls_event_tlsclienterror" id="tls_event_tlsclienterror">#</a></span></h4>
712<div class="api_metadata">
713<span>Added in: v6.0.0</span>
714</div>
715<p>The <code>'tlsClientError'</code> event is emitted when an error occurs before a secure
716connection is established. The listener callback is passed two arguments when
717called:</p>
718<ul>
719<li><code>exception</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a> The <code>Error</code> object describing the error</li>
720<li><code>tlsSocket</code> <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a> The <code>tls.TLSSocket</code> instance from which the
721error originated.</li>
722</ul>
723<h4><code>server.addContext(hostname, context)</code><span><a class="mark" href="#tls_server_addcontext_hostname_context" id="tls_server_addcontext_hostname_context">#</a></span></h4>
724<div class="api_metadata">
725<span>Added in: v0.5.3</span>
726</div>
727<ul>
728<li><code>hostname</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> A SNI host name or wildcard (e.g. <code>'*'</code>)</li>
729<li><code>context</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> An object containing any of the possible properties
730from the <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a> <code>options</code> arguments (e.g. <code>key</code>,
731<code>cert</code>, <code>ca</code>, etc).</li>
732</ul>
733<p>The <code>server.addContext()</code> method adds a secure context that will be used if
734the client request's SNI name matches the supplied <code>hostname</code> (or wildcard).</p>
735<h4><code>server.address()</code><span><a class="mark" href="#tls_server_address" id="tls_server_address">#</a></span></h4>
736<div class="api_metadata">
737<span>Added in: v0.6.0</span>
738</div>
739<ul>
740<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
741</ul>
742<p>Returns the bound address, the address family name, and port of the
743server as reported by the operating system. See <a href="net.html#net_server_address"><code>net.Server.address()</code></a> for
744more information.</p>
745<h4><code>server.close([callback])</code><span><a class="mark" href="#tls_server_close_callback" id="tls_server_close_callback">#</a></span></h4>
746<div class="api_metadata">
747<span>Added in: v0.3.2</span>
748</div>
749<ul>
750<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> A listener callback that will be registered to listen
751for the server instance's <code>'close'</code> event.</li>
752<li>Returns: <a href="tls.html#tls_class_tls_server" class="type">&#x3C;tls.Server></a></li>
753</ul>
754<p>The <code>server.close()</code> method stops the server from accepting new connections.</p>
755<p>This function operates asynchronously. The <code>'close'</code> event will be emitted
756when the server has no more open connections.</p>
757<h4><code>server.connections</code><span><a class="mark" href="#tls_server_connections" id="tls_server_connections">#</a></span></h4>
758<div class="api_metadata">
759<span>Added in: v0.3.2</span><span>Deprecated since: v0.9.7</span>
760</div>
761<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated: Use <a href="net.html#net_server_getconnections_callback"><code>server.getConnections()</code></a> instead.</div><p></p>
762<ul>
763<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
764</ul>
765<p>Returns the current number of concurrent connections on the server.</p>
766<h4><code>server.getTicketKeys()</code><span><a class="mark" href="#tls_server_getticketkeys" id="tls_server_getticketkeys">#</a></span></h4>
767<div class="api_metadata">
768<span>Added in: v3.0.0</span>
769</div>
770<ul>
771<li>Returns: <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> A 48-byte buffer containing the session ticket keys.</li>
772</ul>
773<p>Returns the session ticket keys.</p>
774<p>See <a href="#tls_session_resumption">Session Resumption</a> for more information.</p>
775<h4><code>server.listen()</code><span><a class="mark" href="#tls_server_listen" id="tls_server_listen">#</a></span></h4>
776<p>Starts the server listening for encrypted connections.
777This method is identical to <a href="net.html#net_server_listen"><code>server.listen()</code></a> from <a href="net.html#net_class_net_server"><code>net.Server</code></a>.</p>
778<h4><code>server.setSecureContext(options)</code><span><a class="mark" href="#tls_server_setsecurecontext_options" id="tls_server_setsecurecontext_options">#</a></span></h4>
779<div class="api_metadata">
780<span>Added in: v11.0.0</span>
781</div>
782<ul>
783<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> An object containing any of the possible properties from
784the <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a> <code>options</code> arguments (e.g. <code>key</code>, <code>cert</code>,
785<code>ca</code>, etc).</li>
786</ul>
787<p>The <code>server.setSecureContext()</code> method replaces the secure context of an
788existing server. Existing connections to the server are not interrupted.</p>
789<h4><code>server.setTicketKeys(keys)</code><span><a class="mark" href="#tls_server_setticketkeys_keys" id="tls_server_setticketkeys_keys">#</a></span></h4>
790<div class="api_metadata">
791<span>Added in: v3.0.0</span>
792</div>
793<ul>
794<li><code>keys</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type">&#x3C;TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type">&#x3C;DataView></a> A 48-byte buffer containing the session
795ticket keys.</li>
796</ul>
797<p>Sets the session ticket keys.</p>
798<p>Changes to the ticket keys are effective only for future server connections.
799Existing or currently pending server connections will use the previous keys.</p>
800<p>See <a href="#tls_session_resumption">Session Resumption</a> for more information.</p>
801</section><section><h3>Class: <code>tls.TLSSocket</code><span><a class="mark" href="#tls_class_tls_tlssocket" id="tls_class_tls_tlssocket">#</a></span></h3>
802<div class="api_metadata">
803<span>Added in: v0.11.4</span>
804</div>
805<ul>
806<li>Extends: <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a></li>
807</ul>
808<p>Performs transparent encryption of written data and all required TLS
809negotiation.</p>
810<p>Instances of <code>tls.TLSSocket</code> implement the duplex <a href="stream.html#stream_stream">Stream</a> interface.</p>
811<p>Methods that return TLS connection metadata (e.g.
812<a href="#tls_tlssocket_getpeercertificate_detailed"><code>tls.TLSSocket.getPeerCertificate()</code></a> will only return data while the
813connection is open.</p>
814<h4><code>new tls.TLSSocket(socket[, options])</code><span><a class="mark" href="#tls_new_tls_tlssocket_socket_options" id="tls_new_tls_tlssocket_socket_options">#</a></span></h4>
815<div class="api_metadata">
816<details class="changelog"><summary>History</summary>
817<table>
818<tbody><tr><th>Version</th><th>Changes</th></tr>
819<tr><td>v12.2.0</td>
820<td><p>The <code>enableTrace</code> option is now supported.</p></td></tr>
821<tr><td>v5.0.0</td>
822<td><p>ALPN options are supported now.</p></td></tr>
823<tr><td>v0.11.4</td>
824<td><p><span>Added in: v0.11.4</span></p></td></tr>
825</tbody></table>
826</details>
827</div>
828<ul>
829<li><code>socket</code> <a href="net.html#net_class_net_socket" class="type">&#x3C;net.Socket></a> | <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a>
830On the server side, any <code>Duplex</code> stream. On the client side, any
831instance of <a href="net.html#net_class_net_socket"><code>net.Socket</code></a> (for generic <code>Duplex</code> stream support
832on the client side, <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a> must be used).</li>
833<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a>
834<ul>
835<li><code>enableTrace</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
836<li><code>isServer</code>: The SSL/TLS protocol is asymmetrical, TLSSockets must know if
837they are to behave as a server or a client. If <code>true</code> the TLS socket will be
838instantiated as a server. <strong>Default:</strong> <code>false</code>.</li>
839<li><code>server</code> <a href="net.html#net_class_net_server" class="type">&#x3C;net.Server></a> A <a href="net.html#net_class_net_server"><code>net.Server</code></a> instance.</li>
840<li><code>requestCert</code>: Whether to authenticate the remote peer by requesting a
841certificate. Clients always request a server certificate. Servers
842(<code>isServer</code> is true) may set <code>requestCert</code> to true to request a client
843certificate.</li>
844<li><code>rejectUnauthorized</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
845<li><code>ALPNProtocols</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
846<li><code>SNICallback</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
847<li><code>session</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> A <code>Buffer</code> instance containing a TLS session.</li>
848<li><code>requestOCSP</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If <code>true</code>, specifies that the OCSP status request
849extension will be added to the client hello and an <code>'OCSPResponse'</code> event
850will be emitted on the socket before establishing a secure communication</li>
851<li><code>secureContext</code>: TLS context object created with
852<a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a>. If a <code>secureContext</code> is <em>not</em> provided, one
853will be created by passing the entire <code>options</code> object to
854<code>tls.createSecureContext()</code>.</li>
855<li>...: <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a> options that are used if the
856<code>secureContext</code> option is missing. Otherwise, they are ignored.</li>
857</ul>
858</li>
859</ul>
860<p>Construct a new <code>tls.TLSSocket</code> object from an existing TCP socket.</p>
861<h4>Event: <code>'keylog'</code><span><a class="mark" href="#tls_event_keylog_1" id="tls_event_keylog_1">#</a></span></h4>
862<div class="api_metadata">
863<span>Added in: v12.3.0, v10.20.0</span>
864</div>
865<ul>
866<li><code>line</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> Line of ASCII text, in NSS <code>SSLKEYLOGFILE</code> format.</li>
867</ul>
868<p>The <code>keylog</code> event is emitted on a <code>tls.TLSSocket</code> when key material
869is generated or received by the socket. This keying material can be stored
870for debugging, as it allows captured TLS traffic to be decrypted. It may
871be emitted multiple times, before or after the handshake completes.</p>
872<p>A typical use case is to append received lines to a common text file, which
873is later used by software (such as Wireshark) to decrypt the traffic:</p>
874<pre><code class="language-js"><span class="hljs-keyword">const</span> logFile = fs.<span class="hljs-title function_">createWriteStream</span>(<span class="hljs-string">'/tmp/ssl-keys.log'</span>, { <span class="hljs-attr">flags</span>: <span class="hljs-string">'a'</span> });
875<span class="hljs-comment">// ...</span>
876tlsSocket.<span class="hljs-title function_">on</span>(<span class="hljs-string">'keylog'</span>, <span class="hljs-function">(<span class="hljs-params">line</span>) =></span> logFile.<span class="hljs-title function_">write</span>(line));</code></pre>
877<h4>Event: <code>'OCSPResponse'</code><span><a class="mark" href="#tls_event_ocspresponse" id="tls_event_ocspresponse">#</a></span></h4>
878<div class="api_metadata">
879<span>Added in: v0.11.13</span>
880</div>
881<p>The <code>'OCSPResponse'</code> event is emitted if the <code>requestOCSP</code> option was set
882when the <code>tls.TLSSocket</code> was created and an OCSP response has been received.
883The listener callback is passed a single argument when called:</p>
884<ul>
885<li><code>response</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The server's OCSP response</li>
886</ul>
887<p>Typically, the <code>response</code> is a digitally signed object from the server's CA that
888contains information about server's certificate revocation status.</p>
889<h4>Event: <code>'secureConnect'</code><span><a class="mark" href="#tls_event_secureconnect" id="tls_event_secureconnect">#</a></span></h4>
890<div class="api_metadata">
891<span>Added in: v0.11.4</span>
892</div>
893<p>The <code>'secureConnect'</code> event is emitted after the handshaking process for a new
894connection has successfully completed. The listener callback will be called
895regardless of whether or not the server's certificate has been authorized. It
896is the client's responsibility to check the <code>tlsSocket.authorized</code> property to
897determine if the server certificate was signed by one of the specified CAs. If
898<code>tlsSocket.authorized === false</code>, then the error can be found by examining the
899<code>tlsSocket.authorizationError</code> property. If ALPN was used, the
900<code>tlsSocket.alpnProtocol</code> property can be checked to determine the negotiated
901protocol.</p>
902<p>The <code>'secureConnect'</code> event is not emitted when a <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a> is created
903using the <code>new tls.TLSSocket()</code> constructor.</p>
904<h4>Event: <code>'session'</code><span><a class="mark" href="#tls_event_session" id="tls_event_session">#</a></span></h4>
905<div class="api_metadata">
906<span>Added in: v11.10.0</span>
907</div>
908<ul>
909<li><code>session</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
910</ul>
911<p>The <code>'session'</code> event is emitted on a client <code>tls.TLSSocket</code> when a new session
912or TLS ticket is available. This may or may not be before the handshake is
913complete, depending on the TLS protocol version that was negotiated. The event
914is not emitted on the server, or if a new session was not created, for example,
915when the connection was resumed. For some TLS protocol versions the event may be
916emitted multiple times, in which case all the sessions can be used for
917resumption.</p>
918<p>On the client, the <code>session</code> can be provided to the <code>session</code> option of
919<a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a> to resume the connection.</p>
920<p>See <a href="#tls_session_resumption">Session Resumption</a> for more information.</p>
921<p>For TLSv1.2 and below, <a href="#tls_tlssocket_getsession"><code>tls.TLSSocket.getSession()</code></a> can be called once
922the handshake is complete. For TLSv1.3, only ticket-based resumption is allowed
923by the protocol, multiple tickets are sent, and the tickets aren't sent until
924after the handshake completes. So it is necessary to wait for the
925<code>'session'</code> event to get a resumable session. Applications
926should use the <code>'session'</code> event instead of <code>getSession()</code> to ensure
927they will work for all TLS versions. Applications that only expect to
928get or use one session should listen for this event only once:</p>
929<pre><code class="language-js">tlsSocket.<span class="hljs-title function_">once</span>(<span class="hljs-string">'session'</span>, <span class="hljs-function">(<span class="hljs-params">session</span>) =></span> {
930  <span class="hljs-comment">// The session can be used immediately or later.</span>
931  tls.<span class="hljs-title function_">connect</span>({
932    <span class="hljs-attr">session</span>: session,
933    <span class="hljs-comment">// Other connect options...</span>
934  });
935});</code></pre>
936<h4><code>tlsSocket.address()</code><span><a class="mark" href="#tls_tlssocket_address" id="tls_tlssocket_address">#</a></span></h4>
937<div class="api_metadata">
938<span>Added in: v0.11.4</span>
939</div>
940<ul>
941<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
942</ul>
943<p>Returns the bound <code>address</code>, the address <code>family</code> name, and <code>port</code> of the
944underlying socket as reported by the operating system:
945<code>{ port: 12346, family: 'IPv4', address: '127.0.0.1' }</code>.</p>
946<h4><code>tlsSocket.authorizationError</code><span><a class="mark" href="#tls_tlssocket_authorizationerror" id="tls_tlssocket_authorizationerror">#</a></span></h4>
947<div class="api_metadata">
948<span>Added in: v0.11.4</span>
949</div>
950<p>Returns the reason why the peer's certificate was not been verified. This
951property is set only when <code>tlsSocket.authorized === false</code>.</p>
952<h4><code>tlsSocket.authorized</code><span><a class="mark" href="#tls_tlssocket_authorized" id="tls_tlssocket_authorized">#</a></span></h4>
953<div class="api_metadata">
954<span>Added in: v0.11.4</span>
955</div>
956<ul>
957<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
958</ul>
959<p>Returns <code>true</code> if the peer certificate was signed by one of the CAs specified
960when creating the <code>tls.TLSSocket</code> instance, otherwise <code>false</code>.</p>
961<h4><code>tlsSocket.disableRenegotiation()</code><span><a class="mark" href="#tls_tlssocket_disablerenegotiation" id="tls_tlssocket_disablerenegotiation">#</a></span></h4>
962<div class="api_metadata">
963<span>Added in: v8.4.0</span>
964</div>
965<p>Disables TLS renegotiation for this <code>TLSSocket</code> instance. Once called, attempts
966to renegotiate will trigger an <code>'error'</code> event on the <code>TLSSocket</code>.</p>
967<h4><code>tlsSocket.enableTrace()</code><span><a class="mark" href="#tls_tlssocket_enabletrace" id="tls_tlssocket_enabletrace">#</a></span></h4>
968<div class="api_metadata">
969<span>Added in: v12.2.0</span>
970</div>
971<p>When enabled, TLS packet trace information is written to <code>stderr</code>. This can be
972used to debug TLS connection problems.</p>
973<p>Note: The format of the output is identical to the output of <code>openssl s_client -trace</code> or <code>openssl s_server -trace</code>. While it is produced by OpenSSL's
974<code>SSL_trace()</code> function, the format is undocumented, can change without notice,
975and should not be relied on.</p>
976<h4><code>tlsSocket.encrypted</code><span><a class="mark" href="#tls_tlssocket_encrypted" id="tls_tlssocket_encrypted">#</a></span></h4>
977<div class="api_metadata">
978<span>Added in: v0.11.4</span>
979</div>
980<p>Always returns <code>true</code>. This may be used to distinguish TLS sockets from regular
981<code>net.Socket</code> instances.</p>
982<h4><code>tlsSocket.getCertificate()</code><span><a class="mark" href="#tls_tlssocket_getcertificate" id="tls_tlssocket_getcertificate">#</a></span></h4>
983<div class="api_metadata">
984<span>Added in: v11.2.0</span>
985</div>
986<ul>
987<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
988</ul>
989<p>Returns an object representing the local certificate. The returned object has
990some properties corresponding to the fields of the certificate.</p>
991<p>See <a href="#tls_tlssocket_getpeercertificate_detailed"><code>tls.TLSSocket.getPeerCertificate()</code></a> for an example of the certificate
992structure.</p>
993<p>If there is no local certificate, an empty object will be returned. If the
994socket has been destroyed, <code>null</code> will be returned.</p>
995<h4><code>tlsSocket.getCipher()</code><span><a class="mark" href="#tls_tlssocket_getcipher" id="tls_tlssocket_getcipher">#</a></span></h4>
996<div class="api_metadata">
997<details class="changelog"><summary>History</summary>
998<table>
999<tbody><tr><th>Version</th><th>Changes</th></tr>
1000<tr><td>v13.4.0, v12.16.0</td>
1001<td><p>Return the IETF cipher name as <code>standardName</code>.</p></td></tr>
1002<tr><td>v12.0.0</td>
1003<td><p>Return the minimum cipher version, instead of a fixed string (<code>'TLSv1/SSLv3'</code>).</p></td></tr>
1004<tr><td>v0.11.4</td>
1005<td><p><span>Added in: v0.11.4</span></p></td></tr>
1006</tbody></table>
1007</details>
1008</div>
1009<ul>
1010<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a>
1011<ul>
1012<li><code>name</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> OpenSSL name for the cipher suite.</li>
1013<li><code>standardName</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> IETF name for the cipher suite.</li>
1014<li><code>version</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The minimum TLS protocol version supported by this cipher
1015suite.</li>
1016</ul>
1017</li>
1018</ul>
1019<p>Returns an object containing information on the negotiated cipher suite.</p>
1020<p>For example:</p>
1021<pre><code class="language-json"><span class="hljs-punctuation">{</span>
1022    <span class="hljs-attr">"name"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"AES128-SHA256"</span><span class="hljs-punctuation">,</span>
1023    <span class="hljs-attr">"standardName"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"TLS_RSA_WITH_AES_128_CBC_SHA256"</span><span class="hljs-punctuation">,</span>
1024    <span class="hljs-attr">"version"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"TLSv1.2"</span>
1025<span class="hljs-punctuation">}</span></code></pre>
1026<p>See
1027<a href="https://www.openssl.org/docs/man1.1.1/man3/SSL_CIPHER_get_name.html">SSL_CIPHER_get_name</a>
1028for more information.</p>
1029<h4><code>tlsSocket.getEphemeralKeyInfo()</code><span><a class="mark" href="#tls_tlssocket_getephemeralkeyinfo" id="tls_tlssocket_getephemeralkeyinfo">#</a></span></h4>
1030<div class="api_metadata">
1031<span>Added in: v5.0.0</span>
1032</div>
1033<ul>
1034<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></li>
1035</ul>
1036<p>Returns an object representing the type, name, and size of parameter of
1037an ephemeral key exchange in <a href="#tls_perfect_forward_secrecy">perfect forward secrecy</a> on a client
1038connection. It returns an empty object when the key exchange is not
1039ephemeral. As this is only supported on a client socket; <code>null</code> is returned
1040if called on a server socket. The supported types are <code>'DH'</code> and <code>'ECDH'</code>. The
1041<code>name</code> property is available only when type is <code>'ECDH'</code>.</p>
1042<p>For example: <code>{ type: 'ECDH', name: 'prime256v1', size: 256 }</code>.</p>
1043<h4><code>tlsSocket.getFinished()</code><span><a class="mark" href="#tls_tlssocket_getfinished" id="tls_tlssocket_getfinished">#</a></span></h4>
1044<div class="api_metadata">
1045<span>Added in: v9.9.0</span>
1046</div>
1047<ul>
1048<li>Returns: <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Undefined_type" class="type">&#x3C;undefined></a> The latest <code>Finished</code> message that has been
1049sent to the socket as part of a SSL/TLS handshake, or <code>undefined</code> if
1050no <code>Finished</code> message has been sent yet.</li>
1051</ul>
1052<p>As the <code>Finished</code> messages are message digests of the complete handshake
1053(with a total of 192 bits for TLS 1.0 and more for SSL 3.0), they can
1054be used for external authentication procedures when the authentication
1055provided by SSL/TLS is not desired or is not enough.</p>
1056<p>Corresponds to the <code>SSL_get_finished</code> routine in OpenSSL and may be used
1057to implement the <code>tls-unique</code> channel binding from <a href="https://tools.ietf.org/html/rfc5929">RFC 5929</a>.</p>
1058<h4><code>tlsSocket.getPeerCertificate([detailed])</code><span><a class="mark" href="#tls_tlssocket_getpeercertificate_detailed" id="tls_tlssocket_getpeercertificate_detailed">#</a></span></h4>
1059<div class="api_metadata">
1060<span>Added in: v0.11.4</span>
1061</div>
1062<ul>
1063<li><code>detailed</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Include the full certificate chain if <code>true</code>, otherwise
1064include just the peer's certificate.</li>
1065<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> A certificate object.</li>
1066</ul>
1067<p>Returns an object representing the peer's certificate. If the peer does not
1068provide a certificate, an empty object will be returned. If the socket has been
1069destroyed, <code>null</code> will be returned.</p>
1070<p>If the full certificate chain was requested, each certificate will include an
1071<code>issuerCertificate</code> property containing an object representing its issuer's
1072certificate.</p>
1073<h5>Certificate object<span><a class="mark" href="#tls_certificate_object" id="tls_certificate_object">#</a></span></h5>
1074<div class="api_metadata">
1075<details class="changelog"><summary>History</summary>
1076<table>
1077<tbody><tr><th>Version</th><th>Changes</th></tr>
1078<tr><td>v11.4.0</td>
1079<td><p>Support Elliptic Curve public key info.</p></td></tr>
1080</tbody></table>
1081</details>
1082</div>
1083<p>A certificate object has properties corresponding to the fields of the
1084certificate.</p>
1085<ul>
1086<li><code>raw</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The DER encoded X.509 certificate data.</li>
1087<li><code>subject</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> The certificate subject, described in terms of
1088Country (<code>C:</code>), StateOrProvince (<code>ST</code>), Locality (<code>L</code>), Organization (<code>O</code>),
1089OrganizationalUnit (<code>OU</code>), and CommonName (<code>CN</code>). The CommonName is typically
1090a DNS name with TLS certificates. Example:
1091<code>{C: 'UK', ST: 'BC', L: 'Metro', O: 'Node Fans', OU: 'Docs', CN: 'example.com'}</code>.</li>
1092<li><code>issuer</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> The certificate issuer, described in the same terms as the
1093<code>subject</code>.</li>
1094<li><code>valid_from</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The date-time the certificate is valid from.</li>
1095<li><code>valid_to</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The date-time the certificate is valid to.</li>
1096<li><code>serialNumber</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The certificate serial number, as a hex string.
1097Example: <code>'B9B0D332A1AA5635'</code>.</li>
1098<li><code>fingerprint</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The SHA-1 digest of the DER encoded certificate. It is
1099returned as a <code>:</code> separated hexadecimal string. Example: <code>'2A:7A:C2:DD:...'</code>.</li>
1100<li><code>fingerprint256</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The SHA-256 digest of the DER encoded certificate.
1101It is returned as a <code>:</code> separated hexadecimal string. Example:
1102<code>'2A:7A:C2:DD:...'</code>.</li>
1103<li><code>ext_key_usage</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array" class="type">&#x3C;Array></a> (Optional) The extended key usage, a set of OIDs.</li>
1104<li><code>subjectaltname</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> (Optional) A string containing concatenated names
1105for the subject, an alternative to the <code>subject</code> names.</li>
1106<li><code>infoAccess</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array" class="type">&#x3C;Array></a> (Optional) An array describing the AuthorityInfoAccess,
1107used with OCSP.</li>
1108<li><code>issuerCertificate</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> (Optional) The issuer certificate object. For
1109self-signed certificates, this may be a circular reference.</li>
1110</ul>
1111<p>The certificate may contain information about the public key, depending on
1112the key type.</p>
1113<p>For RSA keys, the following properties may be defined:</p>
1114<ul>
1115<li><code>bits</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> The RSA bit size. Example: <code>1024</code>.</li>
1116<li><code>exponent</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The RSA exponent, as a string in hexadecimal number
1117notation. Example: <code>'0x010001'</code>.</li>
1118<li><code>modulus</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The RSA modulus, as a hexadecimal string. Example:
1119<code>'B56CE45CB7...'</code>.</li>
1120<li><code>pubkey</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The public key.</li>
1121</ul>
1122<p>For EC keys, the following properties may be defined:</p>
1123<ul>
1124<li><code>pubkey</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> The public key.</li>
1125<li><code>bits</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> The key size in bits. Example: <code>256</code>.</li>
1126<li><code>asn1Curve</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> (Optional) The ASN.1 name of the OID of the elliptic
1127curve. Well-known curves are identified by an OID. While it is unusual, it is
1128possible that the curve is identified by its mathematical properties, in which
1129case it will not have an OID. Example: <code>'prime256v1'</code>.</li>
1130<li><code>nistCurve</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> (Optional) The NIST name for the elliptic curve, if it
1131has one (not all well-known curves have been assigned names by NIST). Example:
1132<code>'P-256'</code>.</li>
1133</ul>
1134<p>Example certificate:</p>
1135<!-- eslint-skip -->
1136<pre><code class="language-js">{ <span class="hljs-attr">subject</span>:
1137   { <span class="hljs-attr">OU</span>: [ <span class="hljs-string">'Domain Control Validated'</span>, <span class="hljs-string">'PositiveSSL Wildcard'</span> ],
1138     <span class="hljs-attr">CN</span>: <span class="hljs-string">'*.nodejs.org'</span> },
1139  <span class="hljs-attr">issuer</span>:
1140   { <span class="hljs-attr">C</span>: <span class="hljs-string">'GB'</span>,
1141     <span class="hljs-attr">ST</span>: <span class="hljs-string">'Greater Manchester'</span>,
1142     <span class="hljs-attr">L</span>: <span class="hljs-string">'Salford'</span>,
1143     <span class="hljs-attr">O</span>: <span class="hljs-string">'COMODO CA Limited'</span>,
1144     <span class="hljs-attr">CN</span>: <span class="hljs-string">'COMODO RSA Domain Validation Secure Server CA'</span> },
1145  <span class="hljs-attr">subjectaltname</span>: <span class="hljs-string">'DNS:*.nodejs.org, DNS:nodejs.org'</span>,
1146  <span class="hljs-attr">infoAccess</span>:
1147   { <span class="hljs-string">'CA Issuers - URI'</span>:
1148      [ <span class="hljs-string">'http://crt.comodoca.com/COMODORSADomainValidationSecureServerCA.crt'</span> ],
1149     <span class="hljs-string">'OCSP - URI'</span>: [ <span class="hljs-string">'http://ocsp.comodoca.com'</span> ] },
1150  <span class="hljs-attr">modulus</span>: <span class="hljs-string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span>,
1151  <span class="hljs-attr">exponent</span>: <span class="hljs-string">'0x10001'</span>,
1152  <span class="hljs-attr">pubkey</span>: &#x3C;Buffer ... >,
1153  valid_from: 'Aug 14 00:00:00 2017 GMT',
1154  valid_to: 'Nov 20 23:59:59 2019 GMT',
1155  fingerprint: '01:02:59:D9:C3:D2:0D:08:F7:82:4E:44:A4:B4:53:C5:E2:3A:87:4D',
1156  fingerprint256: '69:AE:1A:6A:D4:3D:C6:C1:1B:EA:C6:23:DE:BA:2A:14:62:62:93:5C:7A:EA:06:41:9B:0B:BC:87:CE:48:4E:02',
1157  ext_key_usage: [ '1.3.6.1.5.5.7.3.1', '1.3.6.1.5.5.7.3.2' ],
1158  serialNumber: '66593D57F20CBC573E433381B5FEC280',
1159  raw: &#x3C;Buffer ... > }</code></pre>
1160<h4><code>tlsSocket.getPeerFinished()</code><span><a class="mark" href="#tls_tlssocket_getpeerfinished" id="tls_tlssocket_getpeerfinished">#</a></span></h4>
1161<div class="api_metadata">
1162<span>Added in: v9.9.0</span>
1163</div>
1164<ul>
1165<li>Returns: <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Undefined_type" class="type">&#x3C;undefined></a> The latest <code>Finished</code> message that is expected
1166or has actually been received from the socket as part of a SSL/TLS handshake,
1167or <code>undefined</code> if there is no <code>Finished</code> message so far.</li>
1168</ul>
1169<p>As the <code>Finished</code> messages are message digests of the complete handshake
1170(with a total of 192 bits for TLS 1.0 and more for SSL 3.0), they can
1171be used for external authentication procedures when the authentication
1172provided by SSL/TLS is not desired or is not enough.</p>
1173<p>Corresponds to the <code>SSL_get_peer_finished</code> routine in OpenSSL and may be used
1174to implement the <code>tls-unique</code> channel binding from <a href="https://tools.ietf.org/html/rfc5929">RFC 5929</a>.</p>
1175<h4><code>tlsSocket.getProtocol()</code><span><a class="mark" href="#tls_tlssocket_getprotocol" id="tls_tlssocket_getprotocol">#</a></span></h4>
1176<div class="api_metadata">
1177<span>Added in: v5.7.0</span>
1178</div>
1179<ul>
1180<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Null_type" class="type">&#x3C;null></a></li>
1181</ul>
1182<p>Returns a string containing the negotiated SSL/TLS protocol version of the
1183current connection. The value <code>'unknown'</code> will be returned for connected
1184sockets that have not completed the handshaking process. The value <code>null</code> will
1185be returned for server sockets or disconnected client sockets.</p>
1186<p>Protocol versions are:</p>
1187<ul>
1188<li><code>'SSLv3'</code></li>
1189<li><code>'TLSv1'</code></li>
1190<li><code>'TLSv1.1'</code></li>
1191<li><code>'TLSv1.2'</code></li>
1192<li><code>'TLSv1.3'</code></li>
1193</ul>
1194<p>See the OpenSSL <a href="https://www.openssl.org/docs/man1.1.1/man3/SSL_get_version.html"><code>SSL_get_version</code></a> documentation for more information.</p>
1195<h4><code>tlsSocket.getSession()</code><span><a class="mark" href="#tls_tlssocket_getsession" id="tls_tlssocket_getsession">#</a></span></h4>
1196<div class="api_metadata">
1197<span>Added in: v0.11.4</span>
1198</div>
1199<ul>
1200<li><a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
1201</ul>
1202<p>Returns the TLS session data or <code>undefined</code> if no session was
1203negotiated. On the client, the data can be provided to the <code>session</code> option of
1204<a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a> to resume the connection. On the server, it may be useful
1205for debugging.</p>
1206<p>See <a href="#tls_session_resumption">Session Resumption</a> for more information.</p>
1207<p>Note: <code>getSession()</code> works only for TLSv1.2 and below. For TLSv1.3, applications
1208must use the <a href="#tls_event_session"><code>'session'</code></a> event (it also works for TLSv1.2 and below).</p>
1209<h4><code>tlsSocket.getSharedSigalgs()</code><span><a class="mark" href="#tls_tlssocket_getsharedsigalgs" id="tls_tlssocket_getsharedsigalgs">#</a></span></h4>
1210<div class="api_metadata">
1211<span>Added in: v12.11.0</span>
1212</div>
1213<ul>
1214<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array" class="type">&#x3C;Array></a> List of signature algorithms shared between the server and
1215the client in the order of decreasing preference.</li>
1216</ul>
1217<p>See
1218<a href="https://www.openssl.org/docs/man1.1.1/man3/SSL_get_shared_sigalgs.html">SSL_get_shared_sigalgs</a>
1219for more information.</p>
1220<h4><code>tlsSocket.exportKeyingMaterial(length, label[, context])</code><span><a class="mark" href="#tls_tlssocket_exportkeyingmaterial_length_label_context" id="tls_tlssocket_exportkeyingmaterial_length_label_context">#</a></span></h4>
1221<div class="api_metadata">
1222<span>Added in: v13.10.0</span>
1223</div>
1224<ul>
1225<li>
1226<p><code>length</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> number of bytes to retrieve from keying material</p>
1227</li>
1228<li>
1229<p><code>label</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> an application specific label, typically this will be a
1230value from the
1231<a href="https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#exporter-labels">IANA Exporter Label Registry</a>.</p>
1232</li>
1233<li>
1234<p><code>context</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> Optionally provide a context.</p>
1235</li>
1236<li>
1237<p>Returns: <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> requested bytes of the keying material</p>
1238</li>
1239</ul>
1240<p>Keying material is used for validations to prevent different kind of attacks in
1241network protocols, for example in the specifications of IEEE 802.1X.</p>
1242<p>Example</p>
1243<pre><code class="language-js"><span class="hljs-keyword">const</span> keyingMaterial = tlsSocket.<span class="hljs-title function_">exportKeyingMaterial</span>(
1244  <span class="hljs-number">128</span>,
1245  <span class="hljs-string">'client finished'</span>);
1246
1247<span class="hljs-comment">/**
1248 Example return value of keyingMaterial:
1249 &#x3C;Buffer 76 26 af 99 c5 56 8e 42 09 91 ef 9f 93 cb ad 6c 7b 65 f8 53 f1 d8 d9
1250    12 5a 33 b8 b5 25 df 7b 37 9f e0 e2 4f b8 67 83 a3 2f cd 5d 41 42 4c 91
1251    74 ef 2c ... 78 more bytes>
1252*/</span></code></pre>
1253<p>See the OpenSSL <a href="https://www.openssl.org/docs/man1.1.1/man3/SSL_export_keying_material.html"><code>SSL_export_keying_material</code></a> documentation for more
1254information.</p>
1255<h4><code>tlsSocket.getTLSTicket()</code><span><a class="mark" href="#tls_tlssocket_gettlsticket" id="tls_tlssocket_gettlsticket">#</a></span></h4>
1256<div class="api_metadata">
1257<span>Added in: v0.11.4</span>
1258</div>
1259<ul>
1260<li><a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a></li>
1261</ul>
1262<p>For a client, returns the TLS session ticket if one is available, or
1263<code>undefined</code>. For a server, always returns <code>undefined</code>.</p>
1264<p>It may be useful for debugging.</p>
1265<p>See <a href="#tls_session_resumption">Session Resumption</a> for more information.</p>
1266<h4><code>tlsSocket.isSessionReused()</code><span><a class="mark" href="#tls_tlssocket_issessionreused" id="tls_tlssocket_issessionreused">#</a></span></h4>
1267<div class="api_metadata">
1268<span>Added in: v0.5.6</span>
1269</div>
1270<ul>
1271<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>true</code> if the session was reused, <code>false</code> otherwise.</li>
1272</ul>
1273<p>See <a href="#tls_session_resumption">Session Resumption</a> for more information.</p>
1274<h4><code>tlsSocket.localAddress</code><span><a class="mark" href="#tls_tlssocket_localaddress" id="tls_tlssocket_localaddress">#</a></span></h4>
1275<div class="api_metadata">
1276<span>Added in: v0.11.4</span>
1277</div>
1278<ul>
1279<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1280</ul>
1281<p>Returns the string representation of the local IP address.</p>
1282<h4><code>tlsSocket.localPort</code><span><a class="mark" href="#tls_tlssocket_localport" id="tls_tlssocket_localport">#</a></span></h4>
1283<div class="api_metadata">
1284<span>Added in: v0.11.4</span>
1285</div>
1286<ul>
1287<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
1288</ul>
1289<p>Returns the numeric representation of the local port.</p>
1290<h4><code>tlsSocket.remoteAddress</code><span><a class="mark" href="#tls_tlssocket_remoteaddress" id="tls_tlssocket_remoteaddress">#</a></span></h4>
1291<div class="api_metadata">
1292<span>Added in: v0.11.4</span>
1293</div>
1294<ul>
1295<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1296</ul>
1297<p>Returns the string representation of the remote IP address. For example,
1298<code>'74.125.127.100'</code> or <code>'2001:4860:a005::68'</code>.</p>
1299<h4><code>tlsSocket.remoteFamily</code><span><a class="mark" href="#tls_tlssocket_remotefamily" id="tls_tlssocket_remotefamily">#</a></span></h4>
1300<div class="api_metadata">
1301<span>Added in: v0.11.4</span>
1302</div>
1303<ul>
1304<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a></li>
1305</ul>
1306<p>Returns the string representation of the remote IP family. <code>'IPv4'</code> or <code>'IPv6'</code>.</p>
1307<h4><code>tlsSocket.remotePort</code><span><a class="mark" href="#tls_tlssocket_remoteport" id="tls_tlssocket_remoteport">#</a></span></h4>
1308<div class="api_metadata">
1309<span>Added in: v0.11.4</span>
1310</div>
1311<ul>
1312<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a></li>
1313</ul>
1314<p>Returns the numeric representation of the remote port. For example, <code>443</code>.</p>
1315<h4><code>tlsSocket.renegotiate(options, callback)</code><span><a class="mark" href="#tls_tlssocket_renegotiate_options_callback" id="tls_tlssocket_renegotiate_options_callback">#</a></span></h4>
1316<div class="api_metadata">
1317<span>Added in: v0.11.8</span>
1318</div>
1319<ul>
1320<li>
1321<p><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a></p>
1322<ul>
1323<li><code>rejectUnauthorized</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If not <code>false</code>, the server certificate is
1324verified against the list of supplied CAs. An <code>'error'</code> event is emitted if
1325verification fails; <code>err.code</code> contains the OpenSSL error code. <strong>Default:</strong>
1326<code>true</code>.</li>
1327<li><code>requestCert</code></li>
1328</ul>
1329</li>
1330<li>
1331<p><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> If <code>renegotiate()</code> returned <code>true</code>, callback is
1332attached once to the <code>'secure'</code> event. If <code>renegotiate()</code> returned <code>false</code>,
1333<code>callback</code> will be called in the next tick with an error, unless the
1334<code>tlsSocket</code> has been destroyed, in which case <code>callback</code> will not be called
1335at all.</p>
1336</li>
1337<li>
1338<p>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>true</code> if renegotiation was initiated, <code>false</code> otherwise.</p>
1339</li>
1340</ul>
1341<p>The <code>tlsSocket.renegotiate()</code> method initiates a TLS renegotiation process.
1342Upon completion, the <code>callback</code> function will be passed a single argument
1343that is either an <code>Error</code> (if the request failed) or <code>null</code>.</p>
1344<p>This method can be used to request a peer's certificate after the secure
1345connection has been established.</p>
1346<p>When running as the server, the socket will be destroyed with an error after
1347<code>handshakeTimeout</code> timeout.</p>
1348<p>For TLSv1.3, renegotiation cannot be initiated, it is not supported by the
1349protocol.</p>
1350<h4><code>tlsSocket.setMaxSendFragment(size)</code><span><a class="mark" href="#tls_tlssocket_setmaxsendfragment_size" id="tls_tlssocket_setmaxsendfragment_size">#</a></span></h4>
1351<div class="api_metadata">
1352<span>Added in: v0.11.11</span>
1353</div>
1354<ul>
1355<li><code>size</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> The maximum TLS fragment size. The maximum value is <code>16384</code>.
1356<strong>Default:</strong> <code>16384</code>.</li>
1357<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a></li>
1358</ul>
1359<p>The <code>tlsSocket.setMaxSendFragment()</code> method sets the maximum TLS fragment size.
1360Returns <code>true</code> if setting the limit succeeded; <code>false</code> otherwise.</p>
1361<p>Smaller fragment sizes decrease the buffering latency on the client: larger
1362fragments are buffered by the TLS layer until the entire fragment is received
1363and its integrity is verified; large fragments can span multiple roundtrips
1364and their processing can be delayed due to packet loss or reordering. However,
1365smaller fragments add extra TLS framing bytes and CPU overhead, which may
1366decrease overall server throughput.</p>
1367</section><section><h3><code>tls.checkServerIdentity(hostname, cert)</code><span><a class="mark" href="#tls_tls_checkserveridentity_hostname_cert" id="tls_tls_checkserveridentity_hostname_cert">#</a></span></h3>
1368<div class="api_metadata">
1369<details class="changelog"><summary>History</summary>
1370<table>
1371<tbody><tr><th>Version</th><th>Changes</th></tr>
1372<tr><td>v14.18.3</td>
1373<td><p>Support for <code>uniformResourceIdentifier</code> subject alternative names has been disabled in response to CVE-2021-44531.</p></td></tr>
1374<tr><td>v0.8.4</td>
1375<td><p><span>Added in: v0.8.4</span></p></td></tr>
1376</tbody></table>
1377</details>
1378</div>
1379<ul>
1380<li><code>hostname</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The host name or IP address to verify the certificate
1381against.</li>
1382<li><code>cert</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> A <a href="#tls_certificate_object">certificate object</a> representing the peer's certificate.</li>
1383<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Undefined_type" class="type">&#x3C;undefined></a></li>
1384</ul>
1385<p>Verifies the certificate <code>cert</code> is issued to <code>hostname</code>.</p>
1386<p>Returns <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a> object, populating it with <code>reason</code>, <code>host</code>, and <code>cert</code> on
1387failure. On success, returns <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Undefined_type" class="type">&#x3C;undefined></a>.</p>
1388<p>This function can be overwritten by providing alternative function as part of
1389the <code>options.checkServerIdentity</code> option passed to <code>tls.connect()</code>. The
1390overwriting function can call <code>tls.checkServerIdentity()</code> of course, to augment
1391the checks done with additional verification.</p>
1392<p>This function is only called if the certificate passed all other checks, such as
1393being issued by trusted CA (<code>options.ca</code>).</p>
1394<p>Earlier versions of Node.js incorrectly accepted certificates for a given
1395<code>hostname</code> if a matching <code>uniformResourceIdentifier</code> subject alternative name
1396was present (see <a href="https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44531">CVE-2021-44531</a>). Applications that wish to accept
1397<code>uniformResourceIdentifier</code> subject alternative names can use a custom
1398<code>options.checkServerIdentity</code> function that implements the desired behavior.</p>
1399</section><section><h3><code>tls.connect(options[, callback])</code><span><a class="mark" href="#tls_tls_connect_options_callback" id="tls_tls_connect_options_callback">#</a></span></h3>
1400<div class="api_metadata">
1401<details class="changelog"><summary>History</summary>
1402<table>
1403<tbody><tr><th>Version</th><th>Changes</th></tr>
1404<tr><td>v14.18.0</td>
1405<td><p>Added <code>onread</code> option.</p></td></tr>
1406<tr><td>v14.1.0</td>
1407<td><p>The <code>highWaterMark</code> option is accepted now.</p></td></tr>
1408<tr><td>v13.6.0, v12.16.0</td>
1409<td><p>The <code>pskCallback</code> option is now supported.</p></td></tr>
1410<tr><td>v12.9.0</td>
1411<td><p>Support the <code>allowHalfOpen</code> option.</p></td></tr>
1412<tr><td>v12.4.0</td>
1413<td><p>The <code>hints</code> option is now supported.</p></td></tr>
1414<tr><td>v12.2.0</td>
1415<td><p>The <code>enableTrace</code> option is now supported.</p></td></tr>
1416<tr><td>v11.8.0, v10.16.0</td>
1417<td><p>The <code>timeout</code> option is supported now.</p></td></tr>
1418<tr><td>v8.0.0</td>
1419<td><p>The <code>lookup</code> option is supported now.</p></td></tr>
1420<tr><td>v8.0.0</td>
1421<td><p>The <code>ALPNProtocols</code> option can be a <code>TypedArray</code> or <code>DataView</code> now.</p></td></tr>
1422<tr><td>v5.0.0</td>
1423<td><p>ALPN options are supported now.</p></td></tr>
1424<tr><td>v5.3.0, v4.7.0</td>
1425<td><p>The <code>secureContext</code> option is supported now.</p></td></tr>
1426<tr><td>v0.11.3</td>
1427<td><p><span>Added in: v0.11.3</span></p></td></tr>
1428</tbody></table>
1429</details>
1430</div>
1431<ul>
1432<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a>
1433<ul>
1434<li><code>enableTrace</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
1435<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Host the client should connect to. <strong>Default:</strong>
1436<code>'localhost'</code>.</li>
1437<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Port the client should connect to.</li>
1438<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Creates Unix socket connection to path. If this option is
1439specified, <code>host</code> and <code>port</code> are ignored.</li>
1440<li><code>socket</code> <a href="stream.html#stream_class_stream_duplex" class="type">&#x3C;stream.Duplex></a> Establish secure connection on a given socket
1441rather than creating a new socket. Typically, this is an instance of
1442<a href="net.html#net_class_net_socket"><code>net.Socket</code></a>, but any <code>Duplex</code> stream is allowed.
1443If this option is specified, <code>path</code>, <code>host</code> and <code>port</code> are ignored,
1444except for certificate validation. Usually, a socket is already connected
1445when passed to <code>tls.connect()</code>, but it can be connected later.
1446Connection/disconnection/destruction of <code>socket</code> is the user's
1447responsibility; calling <code>tls.connect()</code> will not cause <code>net.connect()</code> to be
1448called.</li>
1449<li><code>allowHalfOpen</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If set to <code>false</code>, then the socket will
1450automatically end the writable side when the readable side ends. If the
1451<code>socket</code> option is set, this option has no effect. See the <code>allowHalfOpen</code>
1452option of <a href="net.html#net_class_net_socket"><code>net.Socket</code></a> for details. <strong>Default:</strong> <code>false</code>.</li>
1453<li><code>rejectUnauthorized</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If not <code>false</code>, the server certificate is
1454verified against the list of supplied CAs. An <code>'error'</code> event is emitted if
1455verification fails; <code>err.code</code> contains the OpenSSL error code. <strong>Default:</strong>
1456<code>true</code>.</li>
1457<li><code>pskCallback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a>
1458<ul>
1459<li>hint: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> optional message sent from the server to help client
1460decide which identity to use during negotiation.
1461Always <code>null</code> if TLS 1.3 is used.</li>
1462<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> in the form
1463<code>{ psk: &#x3C;Buffer|TypedArray|DataView>, identity: &#x3C;string> }</code>
1464or <code>null</code> to stop the negotiation process. <code>psk</code> must be
1465compatible with the selected cipher's digest.
1466<code>identity</code> must use UTF-8 encoding.</li>
1467</ul>
1468When negotiating TLS-PSK (pre-shared keys), this function is called
1469with optional identity <code>hint</code> provided by the server or <code>null</code>
1470in case of TLS 1.3 where <code>hint</code> was removed.
1471It will be necessary to provide a custom <code>tls.checkServerIdentity()</code>
1472for the connection as the default one will try to check host name/IP
1473of the server against the certificate but that's not applicable for PSK
1474because there won't be a certificate present.
1475More information can be found in the <a href="https://tools.ietf.org/html/rfc4279">RFC 4279</a>.</li>
1476<li><code>ALPNProtocols</code>: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type">&#x3C;TypedArray[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type">&#x3C;DataView[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type">&#x3C;TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type">&#x3C;DataView></a>
1477An array of strings, <code>Buffer</code>s or <code>TypedArray</code>s or <code>DataView</code>s, or a
1478single <code>Buffer</code> or <code>TypedArray</code> or <code>DataView</code> containing the supported ALPN
1479protocols. <code>Buffer</code>s should have the format <code>[len][name][len][name]...</code>
1480e.g. <code>'\x08http/1.1\x08http/1.0'</code>, where the <code>len</code> byte is the length of the
1481next protocol name. Passing an array is usually much simpler, e.g.
1482<code>['http/1.1', 'http/1.0']</code>. Protocols earlier in the list have higher
1483preference than those later.</li>
1484<li><code>servername</code>: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Server name for the SNI (Server Name Indication) TLS
1485extension. It is the name of the host being connected to, and must be a host
1486name, and not an IP address. It can be used by a multi-homed server to
1487choose the correct certificate to present to the client, see the
1488<code>SNICallback</code> option to <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a>.</li>
1489<li><code>checkServerIdentity(servername, cert)</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> A callback function
1490to be used (instead of the builtin <code>tls.checkServerIdentity()</code> function)
1491when checking the server's host name (or the provided <code>servername</code> when
1492explicitly set) against the certificate. This should return an <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type">&#x3C;Error></a> if
1493verification fails. The method should return <code>undefined</code> if the <code>servername</code>
1494and <code>cert</code> are verified.</li>
1495<li><code>session</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> A <code>Buffer</code> instance, containing TLS session.</li>
1496<li><code>minDHSize</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Minimum size of the DH parameter in bits to accept a
1497TLS connection. When a server offers a DH parameter with a size less
1498than <code>minDHSize</code>, the TLS connection is destroyed and an error is thrown.
1499<strong>Default:</strong> <code>1024</code>.</li>
1500<li><code>highWaterMark</code>: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Consistent with the readable stream <code>highWaterMark</code> parameter.
1501<strong>Default:</strong> <code>16 * 1024</code>.</li>
1502<li><code>secureContext</code>: TLS context object created with
1503<a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a>. If a <code>secureContext</code> is <em>not</em> provided, one
1504will be created by passing the entire <code>options</code> object to
1505<code>tls.createSecureContext()</code>.</li>
1506<li><code>onread</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> If the <code>socket</code> option is missing, incoming data is
1507stored in a single <code>buffer</code> and passed to the supplied <code>callback</code> when
1508data arrives on the socket, otherwise the option is ignored. See the
1509<code>onread</code> option of <a href="net.html#net_class_net_socket"><code>net.Socket</code></a> for details.</li>
1510<li>...: <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a> options that are used if the
1511<code>secureContext</code> option is missing, otherwise they are ignored.</li>
1512<li>...: Any <a href="net.html#net_socket_connect_options_connectlistener"><code>socket.connect()</code></a> option not already listed.</li>
1513</ul>
1514</li>
1515<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1516<li>Returns: <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a></li>
1517</ul>
1518<p>The <code>callback</code> function, if specified, will be added as a listener for the
1519<a href="#tls_event_secureconnect"><code>'secureConnect'</code></a> event.</p>
1520<p><code>tls.connect()</code> returns a <a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a> object.</p>
1521<p>Unlike the <code>https</code> API, <code>tls.connect()</code> does not enable the
1522SNI (Server Name Indication) extension by default, which may cause some
1523servers to return an incorrect certificate or reject the connection
1524altogether. To enable SNI, set the <code>servername</code> option in addition
1525to <code>host</code>.</p>
1526<p>The following illustrates a client for the echo server example from
1527<a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a>:</p>
1528<pre><code class="language-js"><span class="hljs-comment">// Assumes an echo server that is listening on port 8000.</span>
1529<span class="hljs-keyword">const</span> tls = <span class="hljs-built_in">require</span>(<span class="hljs-string">'tls'</span>);
1530<span class="hljs-keyword">const</span> fs = <span class="hljs-built_in">require</span>(<span class="hljs-string">'fs'</span>);
1531
1532<span class="hljs-keyword">const</span> options = {
1533  <span class="hljs-comment">// Necessary only if the server requires client certificate authentication.</span>
1534  <span class="hljs-attr">key</span>: fs.<span class="hljs-title function_">readFileSync</span>(<span class="hljs-string">'client-key.pem'</span>),
1535  <span class="hljs-attr">cert</span>: fs.<span class="hljs-title function_">readFileSync</span>(<span class="hljs-string">'client-cert.pem'</span>),
1536
1537  <span class="hljs-comment">// Necessary only if the server uses a self-signed certificate.</span>
1538  <span class="hljs-attr">ca</span>: [ fs.<span class="hljs-title function_">readFileSync</span>(<span class="hljs-string">'server-cert.pem'</span>) ],
1539
1540  <span class="hljs-comment">// Necessary only if the server's cert isn't for "localhost".</span>
1541  <span class="hljs-attr">checkServerIdentity</span>: <span class="hljs-function">() =></span> { <span class="hljs-keyword">return</span> <span class="hljs-literal">null</span>; },
1542};
1543
1544<span class="hljs-keyword">const</span> socket = tls.<span class="hljs-title function_">connect</span>(<span class="hljs-number">8000</span>, options, <span class="hljs-function">() =></span> {
1545  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'client connected'</span>,
1546              socket.<span class="hljs-property">authorized</span> ? <span class="hljs-string">'authorized'</span> : <span class="hljs-string">'unauthorized'</span>);
1547  process.<span class="hljs-property">stdin</span>.<span class="hljs-title function_">pipe</span>(socket);
1548  process.<span class="hljs-property">stdin</span>.<span class="hljs-title function_">resume</span>();
1549});
1550socket.<span class="hljs-title function_">setEncoding</span>(<span class="hljs-string">'utf8'</span>);
1551socket.<span class="hljs-title function_">on</span>(<span class="hljs-string">'data'</span>, <span class="hljs-function">(<span class="hljs-params">data</span>) =></span> {
1552  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(data);
1553});
1554socket.<span class="hljs-title function_">on</span>(<span class="hljs-string">'end'</span>, <span class="hljs-function">() =></span> {
1555  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'server ends connection'</span>);
1556});</code></pre>
1557</section><section><h3><code>tls.connect(path[, options][, callback])</code><span><a class="mark" href="#tls_tls_connect_path_options_callback" id="tls_tls_connect_path_options_callback">#</a></span></h3>
1558<div class="api_metadata">
1559<span>Added in: v0.11.3</span>
1560</div>
1561<ul>
1562<li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Default value for <code>options.path</code>.</li>
1563<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> See <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a>.</li>
1564<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> See <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a>.</li>
1565<li>Returns: <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a></li>
1566</ul>
1567<p>Same as <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a> except that <code>path</code> can be provided
1568as an argument instead of an option.</p>
1569<p>A path option, if specified, will take precedence over the path argument.</p>
1570</section><section><h3><code>tls.connect(port[, host][, options][, callback])</code><span><a class="mark" href="#tls_tls_connect_port_host_options_callback" id="tls_tls_connect_port_host_options_callback">#</a></span></h3>
1571<div class="api_metadata">
1572<span>Added in: v0.11.3</span>
1573</div>
1574<ul>
1575<li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Default value for <code>options.port</code>.</li>
1576<li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Default value for <code>options.host</code>.</li>
1577<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> See <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a>.</li>
1578<li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> See <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a>.</li>
1579<li>Returns: <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a></li>
1580</ul>
1581<p>Same as <a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a> except that <code>port</code> and <code>host</code> can be provided
1582as arguments instead of options.</p>
1583<p>A port or host option, if specified, will take precedence over any port or host
1584argument.</p>
1585</section><section><h3><code>tls.createSecureContext([options])</code><span><a class="mark" href="#tls_tls_createsecurecontext_options" id="tls_tls_createsecurecontext_options">#</a></span></h3>
1586<div class="api_metadata">
1587<details class="changelog"><summary>History</summary>
1588<table>
1589<tbody><tr><th>Version</th><th>Changes</th></tr>
1590<tr><td>v12.12.0</td>
1591<td><p>Added <code>privateKeyIdentifier</code> and <code>privateKeyEngine</code> options to get private key from an OpenSSL engine.</p></td></tr>
1592<tr><td>v12.11.0</td>
1593<td><p>Added <code>sigalgs</code> option to override supported signature algorithms.</p></td></tr>
1594<tr><td>v12.0.0</td>
1595<td><p>TLSv1.3 support added.</p></td></tr>
1596<tr><td>v11.5.0</td>
1597<td><p>The <code>ca:</code> option now supports <code>BEGIN TRUSTED CERTIFICATE</code>.</p></td></tr>
1598<tr><td>v11.4.0, v10.16.0</td>
1599<td><p>The <code>minVersion</code> and <code>maxVersion</code> can be used to restrict the allowed TLS protocol versions.</p></td></tr>
1600<tr><td>v10.0.0</td>
1601<td><p>The <code>ecdhCurve</code> cannot be set to <code>false</code> anymore due to a change in OpenSSL.</p></td></tr>
1602<tr><td>v9.3.0</td>
1603<td><p>The <code>options</code> parameter can now include <code>clientCertEngine</code>.</p></td></tr>
1604<tr><td>v9.0.0</td>
1605<td><p>The <code>ecdhCurve</code> option can now be multiple <code>':'</code> separated curve names or <code>'auto'</code>.</p></td></tr>
1606<tr><td>v7.3.0</td>
1607<td><p>If the <code>key</code> option is an array, individual entries do not need a <code>passphrase</code> property anymore. <code>Array</code> entries can also just be <code>string</code>s or <code>Buffer</code>s now.</p></td></tr>
1608<tr><td>v5.2.0</td>
1609<td><p>The <code>ca</code> option can now be a single string containing multiple CA certificates.</p></td></tr>
1610<tr><td>v0.11.13</td>
1611<td><p><span>Added in: v0.11.13</span></p></td></tr>
1612</tbody></table>
1613</details>
1614</div>
1615<ul>
1616<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a>
1617<ul>
1618<li><code>ca</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer[]></a> Optionally override the trusted CA
1619certificates. Default is to trust the well-known CAs curated by Mozilla.
1620Mozilla's CAs are completely replaced when CAs are explicitly specified
1621using this option. The value can be a string or <code>Buffer</code>, or an <code>Array</code> of
1622strings and/or <code>Buffer</code>s. Any string or <code>Buffer</code> can contain multiple PEM
1623CAs concatenated together. The peer's certificate must be chainable to a CA
1624trusted by the server for the connection to be authenticated. When using
1625certificates that are not chainable to a well-known CA, the certificate's CA
1626must be explicitly specified as a trusted or the connection will fail to
1627authenticate.
1628If the peer uses a certificate that doesn't match or chain to one of the
1629default CAs, use the <code>ca</code> option to provide a CA certificate that the peer's
1630certificate can match or chain to.
1631For self-signed certificates, the certificate is its own CA, and must be
1632provided.
1633For PEM encoded certificates, supported types are "TRUSTED CERTIFICATE",
1634"X509 CERTIFICATE", and "CERTIFICATE".
1635See also <a href="#tls_tls_rootcertificates"><code>tls.rootCertificates</code></a>.</li>
1636<li><code>cert</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer[]></a> Cert chains in PEM format. One cert
1637chain should be provided per private key. Each cert chain should consist of
1638the PEM formatted certificate for a provided private <code>key</code>, followed by the
1639PEM formatted intermediate certificates (if any), in order, and not
1640including the root CA (the root CA must be pre-known to the peer, see <code>ca</code>).
1641When providing multiple cert chains, they do not have to be in the same
1642order as their private keys in <code>key</code>. If the intermediate certificates are
1643not provided, the peer will not be able to validate the certificate, and the
1644handshake will fail.</li>
1645<li><code>sigalgs</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Colon-separated list of supported signature algorithms.
1646The list can contain digest algorithms (<code>SHA256</code>, <code>MD5</code> etc.), public key
1647algorithms (<code>RSA-PSS</code>, <code>ECDSA</code> etc.), combination of both (e.g
1648'RSA+SHA384') or TLS v1.3 scheme names (e.g. <code>rsa_pss_pss_sha512</code>).
1649See <a href="https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set1_sigalgs_list.html">OpenSSL man pages</a>
1650for more info.</li>
1651<li><code>ciphers</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Cipher suite specification, replacing the default. For
1652more information, see <a href="#tls_modifying_the_default_tls_cipher_suite">modifying the default cipher suite</a>. Permitted
1653ciphers can be obtained via <a href="#tls_tls_getciphers"><code>tls.getCiphers()</code></a>. Cipher names must be
1654uppercased in order for OpenSSL to accept them.</li>
1655<li><code>clientCertEngine</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Name of an OpenSSL engine which can provide the
1656client certificate.</li>
1657<li><code>crl</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer[]></a> PEM formatted CRLs (Certificate
1658Revocation Lists).</li>
1659<li><code>dhparam</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> Diffie-Hellman parameters, required for
1660<a href="#tls_perfect_forward_secrecy">perfect forward secrecy</a>. Use <code>openssl dhparam</code> to create the parameters.
1661The key length must be greater than or equal to 1024 bits or else an error
1662will be thrown. Although 1024 bits is permissible, use 2048 bits or larger
1663for stronger security. If omitted or invalid, the parameters are silently
1664discarded and DHE ciphers will not be available.</li>
1665<li><code>ecdhCurve</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> A string describing a named curve or a colon separated
1666list of curve NIDs or names, for example <code>P-521:P-384:P-256</code>, to use for
1667ECDH key agreement. Set to <code>auto</code> to select the
1668curve automatically. Use <a href="crypto.html#crypto_crypto_getcurves"><code>crypto.getCurves()</code></a> to obtain a list of
1669available curve names. On recent releases, <code>openssl ecparam -list_curves</code>
1670will also display the name and description of each available elliptic curve.
1671<strong>Default:</strong> <a href="#tls_tls_default_ecdh_curve"><code>tls.DEFAULT_ECDH_CURVE</code></a>.</li>
1672<li><code>honorCipherOrder</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> Attempt to use the server's cipher suite
1673preferences instead of the client's. When <code>true</code>, causes
1674<code>SSL_OP_CIPHER_SERVER_PREFERENCE</code> to be set in <code>secureOptions</code>, see
1675<a href="crypto.html#crypto_openssl_options">OpenSSL Options</a> for more information.</li>
1676<li><code>key</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object[]></a> Private keys in PEM format.
1677PEM allows the option of private keys being encrypted. Encrypted keys will
1678be decrypted with <code>options.passphrase</code>. Multiple keys using different
1679algorithms can be provided either as an array of unencrypted key strings or
1680buffers, or an array of objects in the form
1681<code>{pem: &#x3C;string|buffer>[, passphrase: &#x3C;string>]}</code>. The object form can only
1682occur in an array. <code>object.passphrase</code> is optional. Encrypted keys will be
1683decrypted with <code>object.passphrase</code> if provided, or <code>options.passphrase</code> if
1684it is not.</li>
1685<li><code>privateKeyEngine</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Name of an OpenSSL engine to get private key
1686from. Should be used together with <code>privateKeyIdentifier</code>.</li>
1687<li><code>privateKeyIdentifier</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Identifier of a private key managed by
1688an OpenSSL engine. Should be used together with <code>privateKeyEngine</code>.
1689Should not be set together with <code>key</code>, because both options define a
1690private key in different ways.</li>
1691<li><code>maxVersion</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Optionally set the maximum TLS version to allow. One
1692of <code>'TLSv1.3'</code>, <code>'TLSv1.2'</code>, <code>'TLSv1.1'</code>, or <code>'TLSv1'</code>. Cannot be specified
1693along with the <code>secureProtocol</code> option; use one or the other.
1694<strong>Default:</strong> <a href="#tls_tls_default_max_version"><code>tls.DEFAULT_MAX_VERSION</code></a>.</li>
1695<li><code>minVersion</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Optionally set the minimum TLS version to allow. One
1696of <code>'TLSv1.3'</code>, <code>'TLSv1.2'</code>, <code>'TLSv1.1'</code>, or <code>'TLSv1'</code>. Cannot be specified
1697along with the <code>secureProtocol</code> option; use one or the other. Avoid
1698setting to less than TLSv1.2, but it may be required for
1699interoperability.
1700<strong>Default:</strong> <a href="#tls_tls_default_min_version"><code>tls.DEFAULT_MIN_VERSION</code></a>.</li>
1701<li><code>passphrase</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Shared passphrase used for a single private key and/or
1702a PFX.</li>
1703<li><code>pfx</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object[]></a> PFX or PKCS12 encoded
1704private key and certificate chain. <code>pfx</code> is an alternative to providing
1705<code>key</code> and <code>cert</code> individually. PFX is usually encrypted, if it is,
1706<code>passphrase</code> will be used to decrypt it. Multiple PFX can be provided either
1707as an array of unencrypted PFX buffers, or an array of objects in the form
1708<code>{buf: &#x3C;string|buffer>[, passphrase: &#x3C;string>]}</code>. The object form can only
1709occur in an array. <code>object.passphrase</code> is optional. Encrypted PFX will be
1710decrypted with <code>object.passphrase</code> if provided, or <code>options.passphrase</code> if
1711it is not.</li>
1712<li><code>secureOptions</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Optionally affect the OpenSSL protocol behavior,
1713which is not usually necessary. This should be used carefully if at all!
1714Value is a numeric bitmask of the <code>SSL_OP_*</code> options from
1715<a href="crypto.html#crypto_openssl_options">OpenSSL Options</a>.</li>
1716<li><code>secureProtocol</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Legacy mechanism to select the TLS protocol
1717version to use, it does not support independent control of the minimum and
1718maximum version, and does not support limiting the protocol to TLSv1.3. Use
1719<code>minVersion</code> and <code>maxVersion</code> instead. The possible values are listed as
1720<a href="https://www.openssl.org/docs/man1.1.1/man7/ssl.html#Dealing-with-Protocol-Methods">SSL_METHODS</a>, use the function names as strings. For example, use
1721<code>'TLSv1_1_method'</code> to force TLS version 1.1, or <code>'TLS_method'</code> to allow any
1722TLS protocol version up to TLSv1.3. It is not recommended to use TLS
1723versions less than 1.2, but it may be required for interoperability.
1724<strong>Default:</strong> none, see <code>minVersion</code>.</li>
1725<li><code>sessionIdContext</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Opaque identifier used by servers to ensure
1726session state is not shared between applications. Unused by clients.</li>
1727<li><code>ticketKeys</code>: <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> 48-bytes of cryptographically strong pseudo-random
1728data. See <a href="#tls_session_resumption">Session Resumption</a> for more information.</li>
1729<li><code>sessionTimeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> The number of seconds after which a TLS session
1730created by the server will no longer be resumable. See
1731<a href="#tls_session_resumption">Session Resumption</a> for more information. <strong>Default:</strong> <code>300</code>.</li>
1732</ul>
1733</li>
1734</ul>
1735<p><a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a> sets the default value of the <code>honorCipherOrder</code> option
1736to <code>true</code>, other APIs that create secure contexts leave it unset.</p>
1737<p><a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a> uses a 128 bit truncated SHA1 hash value generated
1738from <code>process.argv</code> as the default value of the <code>sessionIdContext</code> option, other
1739APIs that create secure contexts have no default value.</p>
1740<p>The <code>tls.createSecureContext()</code> method creates a <code>SecureContext</code> object. It is
1741usable as an argument to several <code>tls</code> APIs, such as <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a>
1742and <a href="#tls_server_addcontext_hostname_context"><code>server.addContext()</code></a>, but has no public methods.</p>
1743<p>A key is <em>required</em> for ciphers that use certificates. Either <code>key</code> or
1744<code>pfx</code> can be used to provide it.</p>
1745<p>If the <code>ca</code> option is not given, then Node.js will default to using
1746<a href="https://hg.mozilla.org/mozilla-central/raw-file/tip/security/nss/lib/ckfw/builtins/certdata.txt">Mozilla's publicly trusted list of CAs</a>.</p>
1747</section><section><h3><code>tls.createSecurePair([context][, isServer][, requestCert][, rejectUnauthorized][, options])</code><span><a class="mark" href="#tls_tls_createsecurepair_context_isserver_requestcert_rejectunauthorized_options" id="tls_tls_createsecurepair_context_isserver_requestcert_rejectunauthorized_options">#</a></span></h3>
1748<div class="api_metadata">
1749<details class="changelog"><summary>History</summary>
1750<table>
1751<tbody><tr><th>Version</th><th>Changes</th></tr>
1752<tr><td>v5.0.0</td>
1753<td><p>ALPN options are supported now.</p></td></tr>
1754<tr><td>v0.11.3</td>
1755<td><p><span>Deprecated since: v0.11.3</span></p></td></tr>
1756<tr><td>v0.3.2</td>
1757<td><p><span>Added in: v0.3.2</span></p></td></tr>
1758</tbody></table>
1759</details>
1760</div>
1761<p></p><div class="api_stability api_stability_0"><a href="documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated: Use <a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a> instead.</div><p></p>
1762<ul>
1763<li><code>context</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a> A secure context object as returned by
1764<code>tls.createSecureContext()</code></li>
1765<li><code>isServer</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>true</code> to specify that this TLS connection should be
1766opened as a server.</li>
1767<li><code>requestCert</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> <code>true</code> to specify whether a server should request a
1768certificate from a connecting client. Only applies when <code>isServer</code> is <code>true</code>.</li>
1769<li><code>rejectUnauthorized</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If not <code>false</code> a server automatically reject
1770clients with invalid certificates. Only applies when <code>isServer</code> is <code>true</code>.</li>
1771<li><code>options</code>
1772<ul>
1773<li><code>enableTrace</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
1774<li><code>secureContext</code>: A TLS context object from <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a></li>
1775<li><code>isServer</code>: If <code>true</code> the TLS socket will be instantiated in server-mode.
1776<strong>Default:</strong> <code>false</code>.</li>
1777<li><code>server</code> <a href="net.html#net_class_net_server" class="type">&#x3C;net.Server></a> A <a href="net.html#net_class_net_server"><code>net.Server</code></a> instance</li>
1778<li><code>requestCert</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
1779<li><code>rejectUnauthorized</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
1780<li><code>ALPNProtocols</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
1781<li><code>SNICallback</code>: See <a href="#tls_tls_createserver_options_secureconnectionlistener"><code>tls.createServer()</code></a></li>
1782<li><code>session</code> <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> A <code>Buffer</code> instance containing a TLS session.</li>
1783<li><code>requestOCSP</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If <code>true</code>, specifies that the OCSP status request
1784extension will be added to the client hello and an <code>'OCSPResponse'</code> event
1785will be emitted on the socket before establishing a secure communication.</li>
1786</ul>
1787</li>
1788</ul>
1789<p>Creates a new secure pair object with two streams, one of which reads and writes
1790the encrypted data and the other of which reads and writes the cleartext data.
1791Generally, the encrypted stream is piped to/from an incoming encrypted data
1792stream and the cleartext one is used as a replacement for the initial encrypted
1793stream.</p>
1794<p><code>tls.createSecurePair()</code> returns a <code>tls.SecurePair</code> object with <code>cleartext</code> and
1795<code>encrypted</code> stream properties.</p>
1796<p>Using <code>cleartext</code> has the same API as <a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a>.</p>
1797<p>The <code>tls.createSecurePair()</code> method is now deprecated in favor of
1798<code>tls.TLSSocket()</code>. For example, the code:</p>
1799<pre><code class="language-js">pair = tls.<span class="hljs-title function_">createSecurePair</span>(<span class="hljs-comment">/* ... */</span>);
1800pair.<span class="hljs-property">encrypted</span>.<span class="hljs-title function_">pipe</span>(socket);
1801socket.<span class="hljs-title function_">pipe</span>(pair.<span class="hljs-property">encrypted</span>);</code></pre>
1802<p>can be replaced by:</p>
1803<pre><code class="language-js">secureSocket = tls.<span class="hljs-title function_">TLSSocket</span>(socket, options);</code></pre>
1804<p>where <code>secureSocket</code> has the same API as <code>pair.cleartext</code>.</p>
1805</section><section><h3><code>tls.createServer([options][, secureConnectionListener])</code><span><a class="mark" href="#tls_tls_createserver_options_secureconnectionlistener" id="tls_tls_createserver_options_secureconnectionlistener">#</a></span></h3>
1806<div class="api_metadata">
1807<details class="changelog"><summary>History</summary>
1808<table>
1809<tbody><tr><th>Version</th><th>Changes</th></tr>
1810<tr><td>v12.3.0</td>
1811<td><p>The <code>options</code> parameter now supports <code>net.createServer()</code> options.</p></td></tr>
1812<tr><td>v9.3.0</td>
1813<td><p>The <code>options</code> parameter can now include <code>clientCertEngine</code>.</p></td></tr>
1814<tr><td>v8.0.0</td>
1815<td><p>The <code>ALPNProtocols</code> option can be a <code>TypedArray</code> or <code>DataView</code> now.</p></td></tr>
1816<tr><td>v5.0.0</td>
1817<td><p>ALPN options are supported now.</p></td></tr>
1818<tr><td>v0.3.2</td>
1819<td><p><span>Added in: v0.3.2</span></p></td></tr>
1820</tbody></table>
1821</details>
1822</div>
1823<ul>
1824<li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type">&#x3C;Object></a>
1825<ul>
1826<li><code>ALPNProtocols</code>: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type">&#x3C;TypedArray[]></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type">&#x3C;DataView[]></a> | <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type">&#x3C;TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type">&#x3C;DataView></a>
1827An array of strings, <code>Buffer</code>s or <code>TypedArray</code>s or <code>DataView</code>s, or a single
1828<code>Buffer</code> or <code>TypedArray</code> or <code>DataView</code> containing the supported ALPN
1829protocols. <code>Buffer</code>s should have the format <code>[len][name][len][name]...</code>
1830e.g. <code>0x05hello0x05world</code>, where the first byte is the length of the next
1831protocol name. Passing an array is usually much simpler, e.g.
1832<code>['hello', 'world']</code>. (Protocols should be ordered by their priority.)</li>
1833<li><code>clientCertEngine</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> Name of an OpenSSL engine which can provide the
1834client certificate.</li>
1835<li><code>enableTrace</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If <code>true</code>, <a href="#tls_tlssocket_enabletrace"><code>tls.TLSSocket.enableTrace()</code></a> will be
1836called on new connections. Tracing can be enabled after the secure
1837connection is established, but this option must be used to trace the secure
1838connection setup. <strong>Default:</strong> <code>false</code>.</li>
1839<li><code>handshakeTimeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> Abort the connection if the SSL/TLS handshake
1840does not finish in the specified number of milliseconds.
1841A <code>'tlsClientError'</code> is emitted on the <code>tls.Server</code> object whenever
1842a handshake times out. <strong>Default:</strong> <code>120000</code> (120 seconds).</li>
1843<li><code>rejectUnauthorized</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If not <code>false</code> the server will reject any
1844connection which is not authorized with the list of supplied CAs. This
1845option only has an effect if <code>requestCert</code> is <code>true</code>. <strong>Default:</strong> <code>true</code>.</li>
1846<li><code>requestCert</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type">&#x3C;boolean></a> If <code>true</code> the server will request a certificate from
1847clients that connect and attempt to verify that certificate. <strong>Default:</strong>
1848<code>false</code>.</li>
1849<li><code>sessionTimeout</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type">&#x3C;number></a> The number of seconds after which a TLS session
1850created by the server will no longer be resumable. See
1851<a href="#tls_session_resumption">Session Resumption</a> for more information. <strong>Default:</strong> <code>300</code>.</li>
1852<li><code>SNICallback(servername, callback)</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a> A function that will be
1853called if the client supports SNI TLS extension. Two arguments will be
1854passed when called: <code>servername</code> and <code>callback</code>. <code>callback</code> is an
1855error-first callback that takes two optional arguments: <code>error</code> and <code>ctx</code>.
1856<code>ctx</code>, if provided, is a <code>SecureContext</code> instance.
1857<a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a> can be used to get a proper <code>SecureContext</code>.
1858If <code>callback</code> is called with a falsy <code>ctx</code> argument, the default secure
1859context of the server will be used. If <code>SNICallback</code> wasn't provided the
1860default callback with high-level API will be used (see below).</li>
1861<li><code>ticketKeys</code>: <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> 48-bytes of cryptographically strong pseudo-random
1862data. See <a href="#tls_session_resumption">Session Resumption</a> for more information.</li>
1863<li><code>pskCallback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a>
1864<ul>
1865<li>socket: <a href="tls.html#tls_class_tls_tlssocket" class="type">&#x3C;tls.TLSSocket></a> the server <a href="#tls_class_tls_tlssocket"><code>tls.TLSSocket</code></a> instance for
1866this connection.</li>
1867<li>identity: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> identity parameter sent from the client.</li>
1868<li>Returns: <a href="buffer.html#buffer_class_buffer" class="type">&#x3C;Buffer></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray" class="type">&#x3C;TypedArray></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView" class="type">&#x3C;DataView></a> pre-shared key that must either be
1869a buffer or <code>null</code> to stop the negotiation process. Returned PSK must be
1870compatible with the selected cipher's digest.</li>
1871</ul>
1872When negotiating TLS-PSK (pre-shared keys), this function is called
1873with the identity provided by the client.
1874If the return value is <code>null</code> the negotiation process will stop and an
1875"unknown_psk_identity" alert message will be sent to the other party.
1876If the server wishes to hide the fact that the PSK identity was not known,
1877the callback must provide some random data as <code>psk</code> to make the connection
1878fail with "decrypt_error" before negotiation is finished.
1879PSK ciphers are disabled by default, and using TLS-PSK thus
1880requires explicitly specifying a cipher suite with the <code>ciphers</code> option.
1881More information can be found in the <a href="https://tools.ietf.org/html/rfc4279">RFC 4279</a>.</li>
1882<li><code>pskIdentityHint</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> optional hint to send to a client to help
1883with selecting the identity during TLS-PSK negotiation. Will be ignored
1884in TLS 1.3. Upon failing to set pskIdentityHint <code>'tlsClientError'</code> will be
1885emitted with <code>'ERR_TLS_PSK_SET_IDENTIY_HINT_FAILED'</code> code.</li>
1886<li>...: Any <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a> option can be provided. For
1887servers, the identity options (<code>pfx</code>, <code>key</code>/<code>cert</code> or <code>pskCallback</code>)
1888are usually required.</li>
1889<li>...: Any <a href="net.html#net_net_createserver_options_connectionlistener"><code>net.createServer()</code></a> option can be provided.</li>
1890</ul>
1891</li>
1892<li><code>secureConnectionListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type">&#x3C;Function></a></li>
1893<li>Returns: <a href="tls.html#tls_class_tls_server" class="type">&#x3C;tls.Server></a></li>
1894</ul>
1895<p>Creates a new <a href="#tls_class_tls_server"><code>tls.Server</code></a>. The <code>secureConnectionListener</code>, if provided, is
1896automatically set as a listener for the <a href="#tls_event_secureconnection"><code>'secureConnection'</code></a> event.</p>
1897<p>The <code>ticketKeys</code> options is automatically shared between <code>cluster</code> module
1898workers.</p>
1899<p>The following illustrates a simple echo server:</p>
1900<pre><code class="language-js"><span class="hljs-keyword">const</span> tls = <span class="hljs-built_in">require</span>(<span class="hljs-string">'tls'</span>);
1901<span class="hljs-keyword">const</span> fs = <span class="hljs-built_in">require</span>(<span class="hljs-string">'fs'</span>);
1902
1903<span class="hljs-keyword">const</span> options = {
1904  <span class="hljs-attr">key</span>: fs.<span class="hljs-title function_">readFileSync</span>(<span class="hljs-string">'server-key.pem'</span>),
1905  <span class="hljs-attr">cert</span>: fs.<span class="hljs-title function_">readFileSync</span>(<span class="hljs-string">'server-cert.pem'</span>),
1906
1907  <span class="hljs-comment">// This is necessary only if using client certificate authentication.</span>
1908  <span class="hljs-attr">requestCert</span>: <span class="hljs-literal">true</span>,
1909
1910  <span class="hljs-comment">// This is necessary only if the client uses a self-signed certificate.</span>
1911  <span class="hljs-attr">ca</span>: [ fs.<span class="hljs-title function_">readFileSync</span>(<span class="hljs-string">'client-cert.pem'</span>) ]
1912};
1913
1914<span class="hljs-keyword">const</span> server = tls.<span class="hljs-title function_">createServer</span>(options, <span class="hljs-function">(<span class="hljs-params">socket</span>) =></span> {
1915  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'server connected'</span>,
1916              socket.<span class="hljs-property">authorized</span> ? <span class="hljs-string">'authorized'</span> : <span class="hljs-string">'unauthorized'</span>);
1917  socket.<span class="hljs-title function_">write</span>(<span class="hljs-string">'welcome!\n'</span>);
1918  socket.<span class="hljs-title function_">setEncoding</span>(<span class="hljs-string">'utf8'</span>);
1919  socket.<span class="hljs-title function_">pipe</span>(socket);
1920});
1921server.<span class="hljs-title function_">listen</span>(<span class="hljs-number">8000</span>, <span class="hljs-function">() =></span> {
1922  <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'server bound'</span>);
1923});</code></pre>
1924<p>The server can be tested by connecting to it using the example client from
1925<a href="#tls_tls_connect_options_callback"><code>tls.connect()</code></a>.</p>
1926</section><section><h3><code>tls.getCiphers()</code><span><a class="mark" href="#tls_tls_getciphers" id="tls_tls_getciphers">#</a></span></h3>
1927<div class="api_metadata">
1928<span>Added in: v0.10.2</span>
1929</div>
1930<ul>
1931<li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
1932</ul>
1933<p>Returns an array with the names of the supported TLS ciphers. The names are
1934lower-case for historical reasons, but must be uppercased to be used in
1935the <code>ciphers</code> option of <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a>.</p>
1936<p>Cipher names that start with <code>'tls_'</code> are for TLSv1.3, all the others are for
1937TLSv1.2 and below.</p>
1938<pre><code class="language-js"><span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(tls.<span class="hljs-title function_">getCiphers</span>()); <span class="hljs-comment">// ['aes128-gcm-sha256', 'aes128-sha', ...]</span></code></pre>
1939</section><section><h3><code>tls.rootCertificates</code><span><a class="mark" href="#tls_tls_rootcertificates" id="tls_tls_rootcertificates">#</a></span></h3>
1940<div class="api_metadata">
1941<span>Added in: v12.3.0</span>
1942</div>
1943<ul>
1944<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string[]></a></li>
1945</ul>
1946<p>An immutable array of strings representing the root certificates (in PEM format)
1947from the bundled Mozilla CA store as supplied by current Node.js version.</p>
1948<p>The bundled CA store, as supplied by Node.js, is a snapshot of Mozilla CA store
1949that is fixed at release time. It is identical on all supported platforms.</p>
1950</section><section><h3><code>tls.DEFAULT_ECDH_CURVE</code><span><a class="mark" href="#tls_tls_default_ecdh_curve" id="tls_tls_default_ecdh_curve">#</a></span></h3>
1951<div class="api_metadata">
1952<details class="changelog"><summary>History</summary>
1953<table>
1954<tbody><tr><th>Version</th><th>Changes</th></tr>
1955<tr><td>v10.0.0</td>
1956<td><p>Default value changed to <code>'auto'</code>.</p></td></tr>
1957<tr><td>v0.11.13</td>
1958<td><p><span>Added in: v0.11.13</span></p></td></tr>
1959</tbody></table>
1960</details>
1961</div>
1962<p>The default curve name to use for ECDH key agreement in a tls server. The
1963default value is <code>'auto'</code>. See <a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a> for further
1964information.</p>
1965</section><section><h3><code>tls.DEFAULT_MAX_VERSION</code><span><a class="mark" href="#tls_tls_default_max_version" id="tls_tls_default_max_version">#</a></span></h3>
1966<div class="api_metadata">
1967<span>Added in: v11.4.0</span>
1968</div>
1969<ul>
1970<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The default value of the <code>maxVersion</code> option of
1971<a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a>. It can be assigned any of the supported TLS
1972protocol versions, <code>'TLSv1.3'</code>, <code>'TLSv1.2'</code>, <code>'TLSv1.1'</code>, or <code>'TLSv1'</code>.
1973<strong>Default:</strong> <code>'TLSv1.3'</code>, unless changed using CLI options. Using
1974<code>--tls-max-v1.2</code> sets the default to <code>'TLSv1.2'</code>. Using <code>--tls-max-v1.3</code> sets
1975the default to <code>'TLSv1.3'</code>. If multiple of the options are provided, the
1976highest maximum is used.</li>
1977</ul>
1978</section><section><h3><code>tls.DEFAULT_MIN_VERSION</code><span><a class="mark" href="#tls_tls_default_min_version" id="tls_tls_default_min_version">#</a></span></h3>
1979<div class="api_metadata">
1980<span>Added in: v11.4.0</span>
1981</div>
1982<ul>
1983<li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type">&#x3C;string></a> The default value of the <code>minVersion</code> option of
1984<a href="#tls_tls_createsecurecontext_options"><code>tls.createSecureContext()</code></a>. It can be assigned any of the supported TLS
1985protocol versions, <code>'TLSv1.3'</code>, <code>'TLSv1.2'</code>, <code>'TLSv1.1'</code>, or <code>'TLSv1'</code>.
1986<strong>Default:</strong> <code>'TLSv1.2'</code>, unless changed using CLI options. Using
1987<code>--tls-min-v1.0</code> sets the default to <code>'TLSv1'</code>. Using <code>--tls-min-v1.1</code> sets
1988the default to <code>'TLSv1.1'</code>. Using <code>--tls-min-v1.3</code> sets the default to
1989<code>'TLSv1.3'</code>. If multiple of the options are provided, the lowest minimum is
1990used.</li>
1991</ul></section>
1992        <!-- API END -->
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1994    </div>
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2007          }
2008          mq.addEventListener('change', mqChangeListener);
2009          if (themeToggleButton) {
2010            themeToggleButton.addEventListener('click', function() {
2011              mq.removeEventListener('change', mqChangeListener);
2012            }, { once: true });
2013          }
2014        }
2015        if (mq.matches) {
2016          document.body.classList.add('dark-mode');
2017        }
2018      } else if (userSettings === 'true') {
2019        document.body.classList.add('dark-mode');
2020      }
2021      if (themeToggleButton) {
2022        themeToggleButton.hidden = false;
2023        themeToggleButton.addEventListener('click', function() {
2024          sessionStorage.setItem(
2025            kCustomPreference,
2026            document.body.classList.toggle('dark-mode')
2027          );
2028        });
2029      }
2030    }
2031  </script>
2032</body>
2033</html>
2034