diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecT163Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecT163Field.cs | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecT163Field.cs b/crypto/src/math/ec/custom/sec/SecT163Field.cs index 165d5b841..f921a5bc7 100644 --- a/crypto/src/math/ec/custom/sec/SecT163Field.cs +++ b/crypto/src/math/ec/custom/sec/SecT163Field.cs @@ -41,6 +41,47 @@ 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 with bases { 2, 3 } + + ulong[] t0 = Nat192.Create64(); + ulong[] t1 = Nat192.Create64(); + + Square(x, t0); + + // 3 | 162 + SquareN(t0, 1, t1); + Multiply(t0, t1, t0); + SquareN(t1, 1, t1); + Multiply(t0, t1, t0); + + // 3 | 54 + SquareN(t0, 3, t1); + Multiply(t0, t1, t0); + SquareN(t1, 3, t1); + Multiply(t0, t1, t0); + + // 3 | 18 + SquareN(t0, 9, t1); + Multiply(t0, t1, t0); + SquareN(t1, 9, t1); + Multiply(t0, t1, t0); + + // 3 | 6 + SquareN(t0, 27, t1); + Multiply(t0, t1, t0); + SquareN(t1, 27, t1); + Multiply(t0, t1, t0); + + // 2 | 2 + SquareN(t0, 81, t1); + Multiply(t0, t1, z); + } + public static void Multiply(ulong[] x, ulong[] y, ulong[] z) { ulong[] tt = Nat192.CreateExt64(); |