Constrain RSA bit sizes.

The FIPS RSA generation algorithm is unkind to keys with funny bit
sizes. Odd numbers of bits are especially inconvenient, but the sqrt(2)
bound is much simpler if the key size is a multiple of 128 (thus giving
prime sizes a multiple of 64, so the sqrt(2) bound is easier to work

Also impose a minimum RSA key size. 255-bit RSA is far too small as it
is and gives small enough primes that the p-q FIPS bound (2^(n/2-100))
starts risking underflow.

Change-Id: I4583c90b67385e53641ccee9b29044e79e94c920
Reviewed-by: Adam Langley <>
2 files changed
tree: b87445165b0af4cbf2cdec215f4f720e1e9d4802
  1. .github/
  2. crypto/
  3. decrepit/
  4. fuzz/
  5. include/
  6. infra/
  7. ssl/
  8. third_party/
  9. tool/
  10. util/
  11. .clang-format
  12. .gitignore
  15. CMakeLists.txt
  16. codereview.settings


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: