Better test boundary cases of ec_cmp_x_coordinate.

This is done in preparation of generalizing the optimization to all our

Wycheproof happily does cover the case where x needed a reduction, but
they don't appear to check x being just above or below n, only x = p - 1
(adjusted downwards). Also we can tailor the test vectors a bit to the
x == r*z^2 (mod p) strategy to make sure we don't mess that up.

Additionally, the scenario is different for n > p. There is also the
nuisance of EC_FELEM vs EC_SCALAR having different widths. All our
built-in curves are well-behaved (same width, and consistently p < n),
but secp160r1 is reachable from custom curves and violates both
properties. Generate some tests to cover it as well.

Change-Id: Iefa5ebfe689a81870be21f04f5962ab161d38dab
Commit-Queue: David Benjamin <>
CQ-Verified: CQ bot account: <>
Reviewed-by: Adam Langley <>
2 files changed
tree: 739cdeb8871b63f21e379aa1974adc7c0b74071c
  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: