diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecT131Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecT131Field.cs | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecT131Field.cs b/crypto/src/math/ec/custom/sec/SecT131Field.cs index 6a1d2a960..47f97078c 100644 --- a/crypto/src/math/ec/custom/sec/SecT131Field.cs +++ b/crypto/src/math/ec/custom/sec/SecT131Field.cs @@ -40,6 +40,35 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec return z; } + public static void Invert(ulong[] x, ulong[] z) + { + if (Nat192.IsZero64(x)) + throw new InvalidOperationException(); + + // Itoh-Tsujii inversion + + ulong[] t0 = Nat192.Create64(); + ulong[] t1 = Nat192.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); + SquareN(t1, 16, t0); + Multiply(t0, t1, t0); + SquareN(t0, 32, t1); + Multiply(t1, t0, t1); + Square(t1, t1); + Multiply(t1, x, t1); + SquareN(t1, 65, t0); + Multiply(t0, t1, t0); + Square(t0, z); + } + public static void Multiply(ulong[] x, ulong[] y, ulong[] z) { ulong[] tt = Nat192.CreateExt64(); |