diff options
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP256R1Field.cs | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP256R1Field.cs b/crypto/src/math/ec/custom/sec/SecP256R1Field.cs index dd37820b6..a01cb5840 100644 --- a/crypto/src/math/ec/custom/sec/SecP256R1Field.cs +++ b/crypto/src/math/ec/custom/sec/SecP256R1Field.cs @@ -8,6 +8,8 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec // 2^256 - 2^224 + 2^192 + 2^96 - 1 internal static readonly uint[] P = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000000, 0x00000000, 0x00000001, 0xFFFFFFFF }; + private static readonly uint[] _2P = new uint[]{ 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000001, 0x00000000, 0x00000000, + 0x00000002, 0xFFFFFFFE, 0x00000001 }; private const uint P7 = 0xFFFFFFFF; private static readonly uint[] PExt = new uint[]{ 0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 0x00000001, 0xFFFFFFFE, 0x00000001, 0xFFFFFFFE, 0x00000001, 0x00000001, 0xFFFFFFFE, @@ -123,24 +125,19 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec cc >>= 32; int c = (int)cc; - if (c < 0) + if (c > 0) { - do - { - c += (int)Nat256.Add(z, P, z); - } - while (c < 0); + Reduce32((uint)c, z); } else { - while (c > 0) + while (c < -1) { - c += Nat256.Sub(z, P, z); + c += (int)Nat256.Add(z, _2P, z) + 1; } - - if (z[7] == P7 && Nat256.Gte(z, P)) + while (c < 0) { - Nat256.Sub(z, P, z); + c += (int)Nat256.Add(z, P, z); } } } |