using Renci.SshNet.Security.Org.BouncyCastle.Math.Raw; using System; namespace Renci.SshNet.Security.Org.BouncyCastle.Math.EC.Multiplier { internal class FixedPointCombMultiplier : AbstractECMultiplier { protected override ECPoint MultiplyPositive(ECPoint p, BigInteger k) { ECCurve curve = p.Curve; int combSize = FixedPointUtilities.GetCombSize(curve); if (k.BitLength > combSize) throw new InvalidOperationException("fixed-point comb doesn't support scalars larger than the curve order"); FixedPointPreCompInfo fixedPointPreCompInfo = FixedPointUtilities.Precompute(p); ECLookupTable lookupTable = fixedPointPreCompInfo.LookupTable; int width = fixedPointPreCompInfo.Width; int num = (combSize + width - 1) / width; ECPoint eCPoint = curve.Infinity; int num2 = num * width; uint[] array = Nat.FromBigInteger(num2, k); int num3 = num2 - 1; for (int i = 0; i < num; i++) { uint num4 = 0; for (int num5 = num3 - i; num5 >= 0; num5 -= num) { uint num6 = array[num5 >> 5] >> num5; num4 ^= num6 >> 1; num4 <<= 1; num4 ^= num6; } ECPoint b = lookupTable.Lookup((int)num4); eCPoint = eCPoint.TwicePlus(b); } return eCPoint.Add(fixedPointPreCompInfo.Offset); } } }