diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecT283Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecT283Field.cs | 39 |
1 files changed, 37 insertions, 2 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecT283Field.cs b/crypto/src/math/ec/custom/sec/SecT283Field.cs index 9afb27461..903ea02ff 100644 --- a/crypto/src/math/ec/custom/sec/SecT283Field.cs +++ b/crypto/src/math/ec/custom/sec/SecT283Field.cs @@ -48,6 +48,41 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec return z; } + public static void Invert(ulong[] x, ulong[] z) + { + if (Nat320.IsZero64(x)) + throw new InvalidOperationException(); + + // Itoh-Tsujii inversion + + ulong[] t0 = Nat320.Create64(); + ulong[] t1 = Nat320.Create64(); + + Square(x, t0); + Multiply(t0, x, t0); + SquareN(t0, 2, t1); + Multiply(t1, t0, t1); + SquareN(t1, 4, t0); + Multiply(t0, t1, t0); + SquareN(t0, 8, t1); + Multiply(t1, t0, t1); + Square(t1, t1); + Multiply(t1, x, t1); + SquareN(t1, 17, t0); + Multiply(t0, t1, t0); + Square(t0, t0); + Multiply(t0, x, t0); + SquareN(t0, 35, t1); + Multiply(t1, t0, t1); + SquareN(t1, 70, t0); + Multiply(t0, t1, t0); + Square(t0, t0); + Multiply(t0, x, t0); + SquareN(t0, 141, t1); + Multiply(t1, t0, t1); + Square(t1, z); + } + public static void Multiply(ulong[] x, ulong[] y, ulong[] z) { ulong[] tt = Nat320.CreateExt64(); @@ -292,7 +327,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec Debug.Assert(y >> 57 == 0); ulong[] u = new ulong[8]; - // u[0] = 0; + //u[0] = 0; u[1] = y; u[2] = u[1] << 1; u[3] = u[2] ^ y; @@ -306,7 +341,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec int k = 48; do { - j = (uint)(x >> k); + j = (uint)(x >> k); g = u[j & 7] ^ u[(j >> 3) & 7] << 3 ^ u[(j >> 6) & 7] << 6; |