using System; namespace Org.BouncyCastle.Math.EC { public class FpCurve : AbstractFpCurve { private const int FP_DEFAULT_COORDS = 4; protected readonly BigInteger m_q; protected readonly BigInteger m_r; protected readonly FpPoint m_infinity; public virtual BigInteger Q => m_q; public override ECPoint Infinity => m_infinity; public override int FieldSize => m_q.BitLength; [Obsolete("Use constructor taking order/cofactor")] public FpCurve(BigInteger q, BigInteger a, BigInteger b) : this(q, a, b, null, null) { } public FpCurve(BigInteger q, BigInteger a, BigInteger b, BigInteger order, BigInteger cofactor) : this(q, a, b, order, cofactor, false) { } internal FpCurve(BigInteger q, BigInteger a, BigInteger b, BigInteger order, BigInteger cofactor, bool isInternal) : base(q, isInternal) { m_q = q; m_r = FpFieldElement.CalculateResidue(q); m_infinity = new FpPoint(this, null, null); m_a = FromBigInteger(a); m_b = FromBigInteger(b); m_order = order; m_cofactor = cofactor; m_coord = 4; } internal FpCurve(BigInteger q, BigInteger r, ECFieldElement a, ECFieldElement b, BigInteger order, BigInteger cofactor) : base(q, true) { m_q = q; m_r = r; m_infinity = new FpPoint(this, null, null); m_a = a; m_b = b; m_order = order; m_cofactor = cofactor; m_coord = 4; } protected override ECCurve CloneCurve() { return new FpCurve(m_q, m_r, m_a, m_b, m_order, m_cofactor); } public override bool SupportsCoordinateSystem(int coord) { if ((uint)coord <= 2 || coord == 4) return true; return false; } public override ECFieldElement FromBigInteger(BigInteger x) { if (x == null || x.SignValue < 0 || x.CompareTo(m_q) >= 0) throw new ArgumentException("value invalid for Fp field element", "x"); return new FpFieldElement(m_q, m_r, x); } protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y) { return new FpPoint(this, x, y); } protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs) { return new FpPoint(this, x, y, zs); } public override ECPoint ImportPoint(ECPoint p) { if (this != p.Curve && CoordinateSystem == 2 && !p.IsInfinity) { int coordinateSystem = p.Curve.CoordinateSystem; if ((uint)(coordinateSystem - 2) <= 2) return new FpPoint(this, FromBigInteger(p.RawXCoord.ToBigInteger()), FromBigInteger(p.RawYCoord.ToBigInteger()), new ECFieldElement[1] { FromBigInteger(p.GetZCoord(0).ToBigInteger()) }); } return base.ImportPoint(p); } } }