diff options
| -rw-r--r-- | crypto/src/crypto/macs/SipHash.cs | 43 |
1 files changed, 25 insertions, 18 deletions
diff --git a/crypto/src/crypto/macs/SipHash.cs b/crypto/src/crypto/macs/SipHash.cs index 34b0ef090..e1a19fa5b 100644 --- a/crypto/src/crypto/macs/SipHash.cs +++ b/crypto/src/crypto/macs/SipHash.cs @@ -21,7 +21,7 @@ namespace Org.BouncyCastle.Crypto.Macs protected readonly int c, d; protected long k0, k1; - protected long v0, v1, v2, v3, v4; + protected long v0, v1, v2, v3; protected long m = 0; protected int wordPos = 0; @@ -100,7 +100,7 @@ namespace Org.BouncyCastle.Crypto.Macs for (; i < fullWords; i += 8) { ulong n = Pack.LE_To_UInt64(input, offset + i); - m = (long)(((ulong)m >> (64 - bits)) | (n << bits)); + m = (long)((n << bits) | ((ulong)m >> -bits)); ProcessMessageWord(); m = (long)n; } @@ -119,7 +119,10 @@ namespace Org.BouncyCastle.Crypto.Macs public virtual long DoFinal() { - m = (long)(((ulong)m >> ((8 - wordPos) << 3)) | ((ulong)((wordCount << 3) + wordPos) << 56)); + // NOTE: 2 distinct shifts to avoid "64-bit shift" when wordPos == 0 + m = (long)((ulong)m >> ((7 - wordPos) << 3)); + m = (long)((ulong)m >> 8); + m = (long)((ulong)m | ((ulong)((wordCount << 3) + wordPos) << 56)); ProcessMessageWord(); @@ -163,29 +166,33 @@ namespace Org.BouncyCastle.Crypto.Macs protected virtual void ApplySipRounds(int n) { + long r0 = v0, r1 = v1, r2 = v2, r3 = v3; + for (int r = 0; r < n; ++r) { - v0 += v1; - v2 += v3; - v1 = RotateLeft(v1, 13); - v3 = RotateLeft(v3, 16); - v1 ^= v0; - v3 ^= v2; - v0 = RotateLeft(v0, 32); - v2 += v1; - v0 += v3; - v1 = RotateLeft(v1, 17); - v3 = RotateLeft(v3, 21); - v1 ^= v2; - v3 ^= v0; - v2 = RotateLeft(v2, 32); + r0 += r1; + r2 += r3; + r1 = RotateLeft(r1, 13); + r3 = RotateLeft(r3, 16); + r1 ^= r0; + r3 ^= r2; + r0 = RotateLeft(r0, 32); + r2 += r1; + r0 += r3; + r1 = RotateLeft(r1, 17); + r3 = RotateLeft(r3, 21); + r1 ^= r2; + r3 ^= r0; + r2 = RotateLeft(r2, 32); } + + v0 = r0; v1 = r1; v2 = r2; v3 = r3; } protected static long RotateLeft(long x, int n) { ulong ux = (ulong)x; - ux = (ux << n) | (ux >> (64 - n)); + ux = (ux << n) | (ux >> -n); return (long)ux; } } |