tree f45de88910406e34b62fbe3f87508f49e9888c35
parent a7bc94489f265305dcf275fb2907f202ea8e49ce
author David Benjamin <davidben@google.com> 1515512150 -0500
committer Adam Langley <agl@google.com> 1516740590 +0000

Implement fe_sq2_tt with fe_sq_tt.

fiat-crypto only generates fe_mul and fe_sq, but the original Ed25519
implementation we had also had fe_sq2 for computing 2*f^2. Previously,
we inlined a version of fe_mul.

Instead, we could implement it with fe_sq and fe_add. Performance-wise,
this seems to not regress. If anything, it makes it faster?

Before (clang, run for 10 seconds):
Did 243000 Ed25519 key generation operations in 10025910us (24237.2 ops/sec)
Did 250000 Ed25519 signing operations in 10035580us (24911.4 ops/sec)
Did 73305 Ed25519 verify operations in 10071101us (7278.7 ops/sec)
Did 184000 Curve25519 base-point multiplication operations in 10040138us (18326.4 ops/sec)
Did 186000 Curve25519 arbitrary point multiplication operations in 10052721us (18502.5 ops/sec)

After (clang, run for 10 seconds):
Did 242424 Ed25519 key generation operations in 10013117us (24210.6 ops/sec)
Did 253000 Ed25519 signing operations in 10011744us (25270.3 ops/sec)
Did 73899 Ed25519 verify operations in 10048040us (7354.6 ops/sec)
Did 194000 Curve25519 base-point multiplication operations in 10005389us (19389.6 ops/sec)
Did 195000 Curve25519 arbitrary point multiplication operations in 10028443us (19444.7 ops/sec)

Before (clang + OPENSSL_SMALL, run for 10 seconds):
Did 144000 Ed25519 key generation operations in 10019344us (14372.2 ops/sec)
Did 146000 Ed25519 signing operations in 10011653us (14583.0 ops/sec)
Did 74052 Ed25519 verify operations in 10005789us (7400.9 ops/sec)
Did 150000 Curve25519 base-point multiplication operations in 10007468us (14988.8 ops/sec)
Did 91392 Curve25519 arbitrary point multiplication operations in 10057678us (9086.8 ops/sec)

After (clang + OPENSSL_SMALL, run for 10 seconds):
Did 144000 Ed25519 key generation operations in 10066724us (14304.6 ops/sec)
Did 148000 Ed25519 signing operations in 10062043us (14708.7 ops/sec)
Did 74820 Ed25519 verify operations in 10058557us (7438.4 ops/sec)
Did 151000 Curve25519 base-point multiplication operations in 10063492us (15004.7 ops/sec)
Did 90402 Curve25519 arbitrary point multiplication operations in 10049141us (8996.0 ops/sec)

Change-Id: I31e9f61833492c3ff2dfd78e1dee5e06f43c850f
Reviewed-on: https://boringssl-review.googlesource.com/24724
Reviewed-by: Adam Langley <agl@google.com>