1 files changed, 93 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP224K1Curve.cs b/crypto/src/math/ec/custom/sec/SecP224K1Curve.cs
new file mode 100644
index 000000000..5d82eaed8
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP224K1Curve.cs
@@ -0,0 +1,93 @@
+using System;
+
+using Org.BouncyCastle.Math.Field;
+using Org.BouncyCastle.Utilities.Encoders;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+ internal class SecP224K1Curve
+ : ECCurve
+ {
+ public static readonly BigInteger q = new BigInteger(1,
+ Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFE56D"));
+
+ private const int SECP224K1_DEFAULT_COORDS = COORD_JACOBIAN;
+
+ protected readonly SecP224K1Point m_infinity;
+
+ public SecP224K1Curve()
+ : base(FiniteFields.GetPrimeField(q))
+ {
+ this.m_infinity = new SecP224K1Point(this, null, null);
+
+ this.m_a = FromBigInteger(BigInteger.Zero);
+ this.m_b = FromBigInteger(BigInteger.ValueOf(5));
+ this.m_order = new BigInteger(1, Hex.Decode("010000000000000000000000000001DCE8D2EC6184CAF0A971769FB1F7"));
+ this.m_cofactor = BigInteger.One;
+ this.m_coord = SECP224K1_DEFAULT_COORDS;
+ }
+
+ protected override ECCurve CloneCurve()
+ {
+ return new SecP224K1Curve();
+ }
+
+ 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 SecP224K1FieldElement(x);
+ }
+
+ protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression)
+ {
+ return new SecP224K1Point(this, x, y, withCompression);
+ }
+
+ protected override ECPoint DecompressPoint(int yTilde, BigInteger X1)
+ {
+ ECFieldElement x = FromBigInteger(X1);
+ ECFieldElement alpha = x.Square().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 SecP224K1Point(this, x, beta, true);
+ }
+ }
+}
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