diff options
| author | Christian Weisgerber <naddy@cvs.openbsd.org> | 2015-11-06 16:43:52 +0000 |
|---|---|---|
| committer | Christian Weisgerber <naddy@cvs.openbsd.org> | 2015-11-06 16:43:52 +0000 |
| commit | 554b3f253241a16a7778fe21a98038ee7c56ad51 (patch) | |
| tree | edbb667ef218e49f7b6c0dc0f4b32db4bf031462 /sys/crypto/gmac.c | |
| parent | ed78f2ec2d453b616dbcce1b58885169645a7f1e (diff) | |
Instead of multiplying with 0..1, extend the bit into a mask and do an AND.
The same technique was already used a few lines above. ok mikeb@
Diffstat (limited to 'sys/crypto/gmac.c')
| -rw-r--r-- | sys/crypto/gmac.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/sys/crypto/gmac.c b/sys/crypto/gmac.c index eb031546637..4dd2019edb2 100644 --- a/sys/crypto/gmac.c +++ b/sys/crypto/gmac.c @@ -1,4 +1,4 @@ -/* $OpenBSD: gmac.c,v 1.4 2014/11/12 17:52:02 mikeb Exp $ */ +/* $OpenBSD: gmac.c,v 1.5 2015/11/06 16:43:51 naddy Exp $ */ /* * Copyright (c) 2010 Mike Belopuhov <mike@vantronix.net> @@ -38,7 +38,7 @@ ghash_gfmul(uint32_t *X, uint32_t *Y, uint32_t *product) uint32_t v[4]; uint32_t z[4] = { 0, 0, 0, 0}; uint8_t *x = (uint8_t *)X; - uint32_t mask, mul; + uint32_t mask; int i; v[0] = betoh32(Y[0]); @@ -56,11 +56,11 @@ ghash_gfmul(uint32_t *X, uint32_t *Y, uint32_t *product) z[3] ^= v[3] & mask; /* update V */ - mul = v[3] & 1; + mask = ~((v[3] & 1) - 1); v[3] = (v[2] << 31) | (v[3] >> 1); v[2] = (v[1] << 31) | (v[2] >> 1); v[1] = (v[0] << 31) | (v[1] >> 1); - v[0] = (v[0] >> 1) ^ (0xe1000000 * mul); + v[0] = (v[0] >> 1) ^ (0xe1000000 & mask); } product[0] = htobe32(z[0]); |