1Security 2======== 3 4We take the security of ``cryptography`` seriously. The following are a set of 5policies we have adopted to ensure that security issues are addressed in a 6timely fashion. 7 8Infrastructure 9-------------- 10 11In addition to ``cryptography``'s code, we're also concerned with the security 12of the infrastructure we run (primarily ``cryptography.io``). If you discover 13a security vulnerability in our infrastructure, we ask you to report it using 14the same procedure. 15 16What is a security issue? 17------------------------- 18 19Anytime it's possible to write code using ``cryptography``'s public API which 20does not provide the guarantees that a reasonable developer would expect it to 21based on our documentation. 22 23That's a bit academic, but basically it means the scope of what we consider a 24vulnerability is broad, and we do not require a proof of concept or even a 25specific exploit, merely a reasonable threat model under which ``cryptography`` 26could be attacked. 27 28To give a few examples of things we would consider security issues: 29 30* If a recipe, such as Fernet, made it easy for a user to bypass 31 confidentiality or integrity with the public API (e.g. if the API let a user 32 reuse nonces). 33* If, under any circumstances, we used a CSPRNG which wasn't fork-safe. 34* If ``cryptography`` used an API in an underlying C library and failed to 35 handle error conditions safely. 36 37Examples of things we wouldn't consider security issues: 38 39* Offering ECB mode for symmetric encryption in the *Hazmat* layer. Though ECB 40 is critically weak, it is documented as being weak in our documentation. 41* Using a variable time comparison somewhere, if it's not possible to 42 articulate any particular program in which this would result in problematic 43 information disclosure. 44 45In general, if you're unsure, we request that you to default to treating things 46as security issues and handling them sensitively, the worst thing that can 47happen is that we'll ask you to file a public issue. 48 49Reporting a security issue 50-------------------------- 51 52We ask that you do not report security issues to our normal GitHub issue 53tracker. 54 55If you believe you've identified a security issue with ``cryptography``, please 56report it to ``alex.gaynor@gmail.com`` and/or ``paul.l.kehrer@gmail.com``. You 57should verify that your MTA uses TLS to ensure the confidentiality of your 58message. 59 60Once you've submitted an issue via email, you should receive an acknowledgment 61within 48 hours, and depending on the action to be taken, you may receive 62further follow-up emails. 63 64Supported Versions 65------------------ 66 67At any given time, we will provide security support for the `master`_ branch 68as well as the most recent release. 69 70New releases for OpenSSL updates 71-------------------------------- 72 73As of versions 0.5, 1.0.1, and 2.0.0, ``cryptography`` statically links OpenSSL 74in binary distributions for Windows, macOS, and Linux respectively, to ease 75installation. Due to this, ``cryptography`` will release a new version whenever 76OpenSSL has a security or bug fix release to avoid shipping insecure software. 77 78Like all our other releases, this will be announced on the mailing list and we 79strongly recommend that you upgrade as soon as possible. 80 81Disclosure Process 82------------------ 83 84When we become aware of a security bug in ``cryptography``, we will endeavor to 85fix it and issue a release as quickly as possible. We will generally issue a new 86release for any security issue. 87 88The steps for issuing a security release are described in our 89:doc:`/doing-a-release` documentation. 90 91 92.. _`master`: https://github.com/pyca/cryptography 93