| commit | 6c428307d153b43882b407bfe62df8aab317fdce | [log] [tgz] |
|---|---|---|
| author | David Benjamin <davidben@google.com> | Thu May 30 00:10:31 2019 -0400 |
| committer | CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> | Thu May 30 20:44:46 2019 +0000 |
| tree | 947423e4348de22b85242b7e1bbc405df3d82ffb | |
| parent | d72e47fddbbb2938ff3eb737bb4491647fac8bac [diff] |
Split ec_point_mul_scalar into two operations. While it appears that we internally support constant-time dual multiplication, it is not actually constant-time. Integrating the two operations means we hit the doubling branch. Instead, replace the constant-time functions with single multiplication functions, one for arbitrary points and one for the base point. This simplifies timing analysis of the EC_METHODs. This CL only changes the wrapper functions. A subsequent CL will change the EC_METHOD hooks. We conservatively assume EC_POINT_mul callers expect secret scalars and split it into two multiplications and an addition if needed. Update-Note: EC_POINT_mul may get slower if called with both g_scalar and p_scalar non-NULL. If the scalars were secret, this plugs a timing leak (note neither ECDH nor ECDSA signing use such an operation). If acting on public scalars, notably ECDSA verify, this slowdown is not inherently necessary. If necessary, we can expose a public version of ec_point_mul_scalar_public, but callers should be using BoringSSL's ECDSA verify API instead. Change-Id: I9c20b660ce4b58dc633588cfd5b2e97a40203ec3 Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/36224 Commit-Queue: Adam Langley <agl@google.com> Reviewed-by: Adam Langley <agl@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.
There are other files in this directory which might be helpful: