- Initial commit

Runtime/3rdParty/BouncyCastle/math/ec/endo/EndoUtilities.cs

@@ -0,0 +1,83 @@
+#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
+#pragma warning disable
+using System;
+
+using Best.HTTP.SecureProtocol.Org.BouncyCastle.Math.EC.Multiplier;
+
+namespace Best.HTTP.SecureProtocol.Org.BouncyCastle.Math.EC.Endo
+{
+    public abstract class EndoUtilities
+    {
+        public static readonly string PRECOMP_NAME = "bc_endo";
+
+        public static BigInteger[] DecomposeScalar(ScalarSplitParameters p, BigInteger k)
+        {
+            int bits = p.Bits;
+            BigInteger b1 = CalculateB(k, p.G1, bits);
+            BigInteger b2 = CalculateB(k, p.G2, bits);
+
+            BigInteger a = k.Subtract((b1.Multiply(p.V1A)).Add(b2.Multiply(p.V2A)));
+            BigInteger b = (b1.Multiply(p.V1B)).Add(b2.Multiply(p.V2B)).Negate();
+
+            return new BigInteger[]{ a, b };
+        }
+
+        public static ECPoint MapPoint(ECEndomorphism endomorphism, ECPoint p)
+        {
+            EndoPreCompInfo precomp = (EndoPreCompInfo)p.Curve.Precompute(p, PRECOMP_NAME,
+                new MapPointCallback(endomorphism, p));
+            return precomp.MappedPoint;
+        }
+
+        private static BigInteger CalculateB(BigInteger k, BigInteger g, int t)
+        {
+            bool negative = (g.SignValue < 0);
+            BigInteger b = k.Multiply(g.Abs());
+            bool extra = b.TestBit(t - 1);
+            b = b.ShiftRight(t);
+            if (extra)
+            {
+                b = b.Add(BigInteger.One);
+            }
+            return negative ? b.Negate() : b;
+        }
+
+        private class MapPointCallback
+            : IPreCompCallback
+        {
+            private readonly ECEndomorphism m_endomorphism;
+            private readonly ECPoint m_point;
+
+            internal MapPointCallback(ECEndomorphism endomorphism, ECPoint point)
+            {
+                this.m_endomorphism = endomorphism;
+                this.m_point = point;
+            }
+
+            public PreCompInfo Precompute(PreCompInfo existing)
+            {
+                EndoPreCompInfo existingEndo = existing as EndoPreCompInfo;
+
+                if (CheckExisting(existingEndo, m_endomorphism))
+                    return existingEndo;
+
+                ECPoint mappedPoint = m_endomorphism.PointMap.Map(m_point);
+
+                EndoPreCompInfo result = new EndoPreCompInfo();
+                result.Endomorphism = m_endomorphism;
+                result.MappedPoint = mappedPoint;
+                return result;
+            }
+
+            private bool CheckExisting(EndoPreCompInfo existingEndo, ECEndomorphism endomorphism)
+            {
+                return null != existingEndo
+                    && existingEndo.Endomorphism == endomorphism
+                    && existingEndo.MappedPoint != null;
+            }
+
+        }
+    }
+}
+#pragma warning restore
+#endif