using Org.BouncyCastle.Math.EC.Endo; using System; namespace Org.BouncyCastle.Math.EC.Multiplier { public class GlvMultiplier : AbstractECMultiplier { protected readonly ECCurve curve; protected readonly GlvEndomorphism glvEndomorphism; public GlvMultiplier(ECCurve curve, GlvEndomorphism glvEndomorphism) { if (curve == null || curve.Order == null) throw new ArgumentException("Need curve with known group order", "curve"); this.curve = curve; this.glvEndomorphism = glvEndomorphism; } protected override ECPoint MultiplyPositive(ECPoint p, BigInteger k) { if (!curve.Equals(p.Curve)) throw new InvalidOperationException(); BigInteger order = p.Curve.Order; BigInteger[] array = glvEndomorphism.DecomposeScalar(k.Mod(order)); BigInteger k2 = array[0]; BigInteger l = array[1]; if (glvEndomorphism.HasEfficientPointMap) return ECAlgorithms.ImplShamirsTrickWNaf(glvEndomorphism, p, k2, l); ECPoint q = EndoUtilities.MapPoint(glvEndomorphism, p); return ECAlgorithms.ImplShamirsTrickWNaf(p, k2, q, l); } } }