Add a per-SSL TLS 1.3 downgrade enforcement option and improve tests.

Due to non-compliant middleboxes, it is possible we'll need to do some
surgery to this mechanism. Making it per-SSL is a little more flexible
and also eases some tests in Chromium until we get its SSL_CTX usage
fixed up.

Also fix up BoringSSL tests. We forgot to test it at TLS 1.0 and use the
-expect-tls13-downgrade flag.

Bug: 226
Change-Id: Ib39227e74e2d6f5e1fbc1ebcc091e751471b3cdc
Reviewed-by: Steven Valdez <>
Commit-Queue: David Benjamin <>
CQ-Verified: CQ bot account: <>
5 files changed
tree: 6fd231cb03d24b0eca9797192f47fe4d8ff9d12c
  1. .clang-format
  2. .github/
  3. .gitignore
  7. CMakeLists.txt
  15. codereview.settings
  16. crypto/
  17. decrepit/
  18. fipstools/
  19. fuzz/
  20. go.mod
  21. include/
  22. infra/
  23. sources.cmake
  24. ssl/
  25. third_party/
  26. tool/
  27. util/


BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.

Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.

BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.

Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.

There are other files in this directory which might be helpful: