| commit | 3529cba4a554fde0ece75a07178c0dd63f73e409 | [log] [tgz] |
|---|---|---|
| author | David Benjamin <davidben@google.com> | Fri Aug 09 16:59:53 2024 -0400 |
| committer | Boringssl LUCI CQ <boringssl-scoped@luci-project-accounts.iam.gserviceaccount.com> | Wed Aug 14 16:15:39 2024 +0000 |
| tree | 2234e245053cc3e7205da6fcb76a06d33e5c4fe2 | |
| parent | 24bd38f452eb34669d607da4f17e8ca6fc44b30e [diff] |
Cite where BN_div actually comes from After spending a while trying to divine where all the bounds came from, and coming up with some of the messy proofs for why it works, I found this exact algorithm in Knuth, Volume 2, with... different messy proofs. Sadly, this algorithm seems to just be messy. Cite it as reference rather than trying to repeat it in code. As part of this, update the discussion on branches. That was added in https://boringssl-review.googlesource.com/c/boringssl/+/9105, back when BN_div was used on secret inputs. It no longer is and, back then, the function still wasn't constant-time anyway. We could, in principle, restore the special cases now. But this would be more complicated and diverge from Knuth's formulation, so let's just keep it simple. (Although it might actually be a hair faster. We care about this function to compute R^2 mod n, and the special case would save an extra iteration through the loop. Though I think that optimization could actually be restored with much, much less code than OpenSSL originally did it. Probably not worth the fuss.) Subsequent CLs will clean this code up in reference to Knuth's formulation. Bug: 358687140 Change-Id: I56da99c560b845f1736ab86edc79b8e711890fe3 Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/70170 Reviewed-by: Bob Beck <bbe@google.com> Commit-Queue: David Benjamin <davidben@google.com>
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.
Project links:
There are other files in this directory which might be helpful: