diff options
| author | Peter Dettman <peter.dettman@bouncycastle.org> | 2014-03-05 17:35:58 +0700 |
|---|---|---|
| committer | Peter Dettman <peter.dettman@bouncycastle.org> | 2014-03-05 17:35:58 +0700 |
| commit | 866a2af68ef7a6f65ff22035bc691bda8409c27a (patch) | |
| tree | 12c46feb2e501a11314810db4ae38c013972518b /crypto/src/math/ec/custom | |
| parent | Use Nat methods instead of specific Nat*.*Ext methods (diff) | |
| download | BouncyCastle.NET-ed25519-866a2af68ef7a6f65ff22035bc691bda8409c27a.tar.xz | |
Reduction optimization for secp256r1
Diffstat (limited to 'crypto/src/math/ec/custom')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP256R1Field.cs | 78 |
1 files changed, 73 insertions, 5 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP256R1Field.cs b/crypto/src/math/ec/custom/sec/SecP256R1Field.cs index cd4702f16..383b42a5e 100644 --- a/crypto/src/math/ec/custom/sec/SecP256R1Field.cs +++ b/crypto/src/math/ec/custom/sec/SecP256R1Field.cs @@ -21,7 +21,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec uint c = Nat256.Add(x, y, z); if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P))) { - Nat256.SubFrom(P, z); + AddPInvTo(z); } } @@ -39,7 +39,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec uint c = Nat.Inc(8, x, z); if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P))) { - Nat256.SubFrom(P, z); + AddPInvTo(z); } } @@ -180,7 +180,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec if (cc != 0 || (z[7] == P7 && Nat256.Gte(z, P))) { - Nat256.SubFrom(P, z); + AddPInvTo(z); } } @@ -211,7 +211,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec int c = Nat256.Sub(x, y, z); if (c != 0) { - Nat256.AddTo(P, z); + SubPInvFrom(z); } } @@ -229,8 +229,76 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec uint c = Nat.ShiftUpBit(8, x, 0, z); if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P))) { - Nat256.SubFrom(P, z); + AddPInvTo(z); + } + } + + private static void AddPInvTo(uint[] z) + { + long c = (long)z[0] + 1; + z[0] = (uint)c; + c >>= 32; + if (c != 0) + { + c += (long)z[1]; + z[1] = (uint)c; + c >>= 32; + c += (long)z[2]; + z[2] = (uint)c; + c >>= 32; + } + c += (long)z[3] - 1; + z[3] = (uint)c; + c >>= 32; + if (c != 0) + { + c += (long)z[4]; + z[4] = (uint)c; + c >>= 32; + c += (long)z[5]; + z[5] = (uint)c; + c >>= 32; + } + c += (long)z[6] - 1; + z[6] = (uint)c; + c >>= 32; + c += (long)z[7] + 1; + z[7] = (uint)c; + //c >>= 32; + } + + private static void SubPInvFrom(uint[] z) + { + long c = (long)z[0] - 1; + z[0] = (uint)c; + c >>= 32; + if (c != 0) + { + c += (long)z[1]; + z[1] = (uint)c; + c >>= 32; + c += (long)z[2]; + z[2] = (uint)c; + c >>= 32; + } + c += (long)z[3] + 1; + z[3] = (uint)c; + c >>= 32; + if (c != 0) + { + c += (long)z[4]; + z[4] = (uint)c; + c >>= 32; + c += (long)z[5]; + z[5] = (uint)c; + c >>= 32; } + c += (long)z[6] + 1; + z[6] = (uint)c; + c >>= 32; + c += (long)z[7] - 1; + z[7] = (uint)c; + //c >>= 32; } } } |