1--- 2c: Copyright (C) Daniel Stenberg, <daniel.se>, et al. 3SPDX-License-Identifier: curl 4Title: CURLOPT_SSL_CIPHER_LIST 5Section: 3 6Source: libcurl 7See-also: 8 - CURLOPT_PROXY_SSL_CIPHER_LIST (3) 9 - CURLOPT_PROXY_TLS13_CIPHERS (3) 10 - CURLOPT_SSLVERSION (3) 11 - CURLOPT_TLS13_CIPHERS (3) 12 - CURLOPT_USE_SSL (3) 13--- 14 15# NAME 16 17CURLOPT_SSL_CIPHER_LIST - ciphers to use for TLS 18 19# SYNOPSIS 20 21~~~c 22#include <curl/curl.h> 23 24CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_CIPHER_LIST, char *list); 25~~~ 26 27# DESCRIPTION 28 29Pass a char pointer, pointing to a null-terminated string holding the list of 30ciphers to use for the SSL connection. The list must be syntactically correct, 31it consists of one or more cipher strings separated by colons. Commas or 32spaces are also acceptable separators but colons are normally used, !, - and 33+ can be used as operators. 34 35For OpenSSL and GnuTLS valid examples of cipher lists include **RC4-SHA**, 36**SHA1+DES**, **TLSv1** and **DEFAULT**. The default list is normally set when 37you compile OpenSSL. 38 39For WolfSSL, valid examples of cipher lists include **ECDHE-RSA-RC4-SHA**, 40**AES256-SHA:AES256-SHA256**, etc. 41 42For BearSSL, valid examples of cipher lists include 43**ECDHE-RSA-CHACHA20-POLY1305:ECDHE-RSA-AES128-GCM-SHA256**, or when using 44IANA names 45**TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256**, 46etc. With BearSSL you do not add/remove ciphers. If one uses this option then 47all known ciphers are disabled and only those passed in are enabled. 48 49For Schannel, you can use this option to set algorithms but not specific 50cipher suites. Refer to the ciphers lists document for algorithms. 51 52Find more details about cipher lists on this URL: 53 54 https://curl.se/docs/ssl-ciphers.html 55 56The application does not have to keep the string around after setting this 57option. 58 59# DEFAULT 60 61NULL, use internal default 62 63# PROTOCOLS 64 65All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc. 66 67# EXAMPLE 68 69~~~c 70int main(void) 71{ 72 CURL *curl = curl_easy_init(); 73 if(curl) { 74 CURLcode res; 75 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/"); 76 curl_easy_setopt(curl, CURLOPT_SSL_CIPHER_LIST, "TLSv1"); 77 res = curl_easy_perform(curl); 78 curl_easy_cleanup(curl); 79 } 80} 81~~~ 82 83# AVAILABILITY 84 85Added in 7.9, in 7.83.0 for BearSSL 86 87If built TLS enabled. 88 89# RETURN VALUE 90 91Returns CURLE_OK if TLS is supported, CURLE_UNKNOWN_OPTION if not, or 92CURLE_OUT_OF_MEMORY if there was insufficient heap space. 93