tree d854abbf40375cbced0bebe45c52ecbd51b2fa33
parent e9a32991a82ef02a1e74f495dcc0785239782bfe
author Filippo Valsorda <filippo@golang.org> 1620249345 -0400
committer Filippo Valsorda <filippo@golang.org> 1620250014 +0000

curve25519: replace field implementation with filippo.io/edwards25519

This imports the crypto/ed25519/internal/edwards25519/field package from
CL 276272, and uses it in x/crypto/curve25519.

The ScalarMult code was ported 1:1 from curve25519_generic.go.

                                old code lines     new code lines

Go                              896                463
Assembly (manually written)     1772 (1772)        362 (34)

43% performance loss on amd64, 33% loss on 386, and 45% gain on arm64.
Feels worth it to remove 1700 lines of manually written assembly.

Apple M1

name               old time/op  new time/op  delta
X25519Basepoint-8  85.0µs ± 1%  46.4µs ± 0%  -45.39%  (p=0.000 n=10+9)
X25519-8           84.4µs ± 0%  46.7µs ± 2%  -44.76%  (p=0.000 n=8+9)

Intel(R) Core(TM) i5-7400 CPU @ 3.00GHz

name               old time/op  new time/op  delta
X25519Basepoint-4  42.6µs ± 1%  60.9µs ± 1%  +43.22%  (p=0.000 n=9+10)
X25519-4           42.5µs ± 1%  60.9µs ± 0%  +43.17%  (p=0.000 n=9+9)

Intel(R) Core(TM) i5-7400 CPU @ 3.00GHz [GOARCH=386]

name               old time/op  new time/op  delta
X25519Basepoint-4   530µs ± 1%   703µs ± 1%  +32.81%  (p=0.000 n=10+10)
X25519-4            530µs ± 1%   706µs ± 1%  +33.18%  (p=0.000 n=10+10)

Change-Id: I1dc62a6a3a3e417a1366ff873c475087a0395124
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/315269
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Filippo Valsorda <filippo@golang.org>
Trust: Katie Hockman <katie@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>