diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecT113R2Curve.cs')
-rw-r--r-- | crypto/src/math/ec/custom/sec/SecT113R2Curve.cs | 92 |
1 files changed, 0 insertions, 92 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs b/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs index a02db6b25..abfd26d5b 100644 --- a/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs +++ b/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs @@ -70,98 +70,6 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec get { return false; } } - /** - * Decompresses a compressed point P = (xp, yp) (X9.62 s 4.2.2). - * - * @param yTilde - * ~yp, an indication bit for the decompression of yp. - * @param X1 - * The field element xp. - * @return the decompressed point. - */ - protected override ECPoint DecompressPoint(int yTilde, BigInteger X1) - { - ECFieldElement x = FromBigInteger(X1), y = null; - if (x.IsZero) - { - y = B.Sqrt(); - } - else - { - ECFieldElement beta = x.Square().Invert().Multiply(B).Add(A).Add(x); - ECFieldElement z = SolveQuadraticEquation(beta); - if (z != null) - { - if (z.TestBitZero() != (yTilde == 1)) - { - z = z.AddOne(); - } - - switch (this.CoordinateSystem) - { - case COORD_LAMBDA_AFFINE: - case COORD_LAMBDA_PROJECTIVE: - { - y = z.Add(x); - break; - } - default: - { - y = z.Multiply(x); - break; - } - } - } - } - - if (y == null) - throw new ArgumentException("Invalid point compression"); - - return this.CreateRawPoint(x, y, true); - } - - /** - * Solves a quadratic equation <code>z<sup>2</sup> + z = beta</code>(X9.62 - * D.1.6) The other solution is <code>z + 1</code>. - * - * @param beta - * The value to solve the quadratic equation for. - * @return the solution for <code>z<sup>2</sup> + z = beta</code> or - * <code>null</code> if no solution exists. - */ - private ECFieldElement SolveQuadraticEquation(ECFieldElement beta) - { - if (beta.IsZero) - { - return beta; - } - - ECFieldElement zeroElement = FromBigInteger(BigInteger.Zero); - - ECFieldElement z = null; - ECFieldElement gamma = null; - - Random rand = new Random(); - do - { - ECFieldElement t = FromBigInteger(new BigInteger(113, rand)); - z = zeroElement; - ECFieldElement w = beta; - for (int i = 1; i < 113; i++) - { - ECFieldElement w2 = w.Square(); - z = z.Square().Add(w2.Multiply(t)); - w = w2.Add(beta); - } - if (!w.IsZero) - return null; - gamma = z.Square().Add(z); - } - while (gamma.IsZero); - - return z; - } - public virtual int M { get { return 113; } |