diff options
Diffstat (limited to 'crypto/clmul.c')
-rw-r--r-- | crypto/clmul.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/crypto/clmul.c b/crypto/clmul.c index 36ada1b..9e3e61a 100644 --- a/crypto/clmul.c +++ b/crypto/clmul.c @@ -92,3 +92,20 @@ uint64_t clmul_32(uint32_t n, uint32_t m32) } return r; } + +Int128 clmul_64_gen(uint64_t n, uint64_t m) +{ + uint64_t rl = 0, rh = 0; + + /* Bit 0 can only influence the low 64-bit result. */ + if (n & 1) { + rl = m; + } + + for (int i = 1; i < 64; ++i) { + uint64_t mask = -((n >> i) & 1); + rl ^= (m << i) & mask; + rh ^= (m >> (64 - i)) & mask; + } + return int128_make128(rl, rh); +} |