diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP224R1Curve.cs')
-rw-r--r-- | crypto/src/math/ec/custom/sec/SecP224R1Curve.cs | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP224R1Curve.cs b/crypto/src/math/ec/custom/sec/SecP224R1Curve.cs new file mode 100644 index 000000000..ee0aa94a4 --- /dev/null +++ b/crypto/src/math/ec/custom/sec/SecP224R1Curve.cs @@ -0,0 +1,96 @@ +using System; + +using Org.BouncyCastle.Math.Field; +using Org.BouncyCastle.Utilities.Encoders; + +namespace Org.BouncyCastle.Math.EC.Custom.Sec +{ + internal class SecP224R1Curve + : ECCurve + { + public static readonly BigInteger q = new BigInteger(1, + Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF000000000000000000000001")); + + private const int SecP224R1_DEFAULT_COORDS = COORD_JACOBIAN; + + protected readonly SecP224R1Point m_infinity; + + public SecP224R1Curve() + : base(FiniteFields.GetPrimeField(q)) + { + this.m_infinity = new SecP224R1Point(this, null, null); + + this.m_a = FromBigInteger(new BigInteger(1, + Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFE"))); + this.m_b = FromBigInteger(new BigInteger(1, + Hex.Decode("B4050A850C04B3ABF54132565044B0B7D7BFD8BA270B39432355FFB4"))); + this.m_order = new BigInteger(1, Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFF16A2E0B8F03E13DD29455C5C2A3D")); + this.m_cofactor = BigInteger.One; + + this.m_coord = SecP224R1_DEFAULT_COORDS; + } + + protected override ECCurve CloneCurve() + { + return new SecP224R1Curve(); + } + + public override bool SupportsCoordinateSystem(int coord) + { + switch (coord) + { + case COORD_JACOBIAN: + return true; + default: + return false; + } + } + + public virtual BigInteger Q + { + get { return q; } + } + + public override ECPoint Infinity + { + get { return m_infinity; } + } + + public override int FieldSize + { + get { return q.BitLength; } + } + + public override ECFieldElement FromBigInteger(BigInteger x) + { + return new SecP224R1FieldElement(x); + } + + protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression) + { + return new SecP224R1Point(this, x, y, withCompression); + } + + protected override ECPoint DecompressPoint(int yTilde, BigInteger X1) + { + ECFieldElement x = FromBigInteger(X1); + ECFieldElement alpha = x.Square().Add(A).Multiply(x).Add(B); + ECFieldElement beta = alpha.Sqrt(); + + // + // if we can't find a sqrt we haven't got a point on the + // curve - run! + // + if (beta == null) + throw new ArithmeticException("Invalid point compression"); + + if (beta.TestBitZero() != (yTilde == 1)) + { + // Use the other root + beta = beta.Negate(); + } + + return new SecP224R1Point(this, x, beta, true); + } + } +} |