tree b43eb0386ffe3dc358b147e3bfb9aa1362526f1f
parent b55a8c1580479e6a3a26e32d103b28f3caf27b2e
author David Benjamin <davidben@google.com> 1589233437 -0400
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1589305135 +0000

Use public multi-scalar mults in Trust Tokens where applicable.

The input points are all public, so we can use a faster multi-scalar
multiplication. This generalizes ec_point_mul_scalar_public to
ec_point_mul_scalar_public_batch. To support the batched DLEQ
construction, this function takes an arbirarily-length array of points
and allocates some temporaries if necessary.

First, to confirm that this doesn't affect the basic ECDSA verify case:
Before:
Did 6324 ECDSA P-384 verify operations in 3069342us (2060.4 ops/sec)
After:
Did 6324 ECDSA P-384 verify operations in 3063355us (2064.4 ops/sec) [+0.2%]

Results for Trust Tokens issue (Exp1) and finish_issuance (both):
Before:
Did 147 TrustToken-Exp0-Batch1 finish_issuance operations in 2059145us (71.4 ops/sec)
Did 14 TrustToken-Exp0-Batch10 finish_issuance operations in 2085888us (6.7 ops/sec)
Did 357 TrustToken-Exp1-Batch1 issue operations in 2068238us (172.6 ops/sec)
Did 286 TrustToken-Exp1-Batch1 finish_issuance operations in 2090932us (136.8 ops/sec)
Did 63 TrustToken-Exp1-Batch10 issue operations in 2068201us (30.5 ops/sec)
Did 56 TrustToken-Exp1-Batch10 finish_issuance operations in 2064796us (27.1 ops/sec)

After:
Did 168 TrustToken-Exp0-Batch1 finish_issuance operations in 2058891us (81.6 ops/sec) [+14.3%]
Did 16 TrustToken-Exp0-Batch10 finish_issuance operations in 2075742us (7.7 ops/sec) [+14.8%]
Did 378 TrustToken-Exp1-Batch1 issue operations in 2067956us (182.8 ops/sec) [+5.9%]
Did 336 TrustToken-Exp1-Batch1 finish_issuance operations in 2097757us (160.2 ops/sec) [+17.1%]
Did 105 TrustToken-Exp1-Batch10 issue operations in 2069934us (50.7 ops/sec) [+66.5%]
Did 88 TrustToken-Exp1-Batch10 finish_issuance operations in 2014621us (43.7 ops/sec) [+61.1%]

(This CL doesn't affect other operations.)

Change-Id: Ie643b06f44990ab52bf892a007732fde61cdffe5
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/41285
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>