Initial implementation of SM2 elliptic curve

- includes custom curve code
- add lots of OIDs from GM standard

1 files changed, 213 insertions, 0 deletions

diff --git a/crypto/src/math/ec/custom/gm/SM2P256V1FieldElement.cs b/crypto/src/math/ec/custom/gm/SM2P256V1FieldElement.cs
new file mode 100644
index 000000000..669c73bd2
--- /dev/null
+++ b/crypto/src/math/ec/custom/gm/SM2P256V1FieldElement.cs
@@ -0,0 +1,213 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Math.EC.Custom.GM
+{
+    internal class SM2P256V1FieldElement
+        : ECFieldElement
+    {
+        public static readonly BigInteger Q = SM2P256V1Curve.q;
+
+        protected internal readonly uint[] x;
+
+        public SM2P256V1FieldElement(BigInteger x)
+        {
+            if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0)
+                throw new ArgumentException("value invalid for SM2P256V1FieldElement", "x");
+
+            this.x = SM2P256V1Field.FromBigInteger(x);
+        }
+
+        public SM2P256V1FieldElement()
+        {
+            this.x = Nat256.Create();
+        }
+
+        protected internal SM2P256V1FieldElement(uint[] x)
+        {
+            this.x = x;
+        }
+
+        public override bool IsZero
+        {
+            get { return Nat256.IsZero(x); }
+        }
+
+        public override bool IsOne
+        {
+            get { return Nat256.IsOne(x); }
+        }
+
+        public override bool TestBitZero()
+        {
+            return Nat256.GetBit(x, 0) == 1;
+        }
+
+        public override BigInteger ToBigInteger()
+        {
+            return Nat256.ToBigInteger(x);
+        }
+
+        public override string FieldName
+        {
+            get { return "SM2P256V1Field"; }
+        }
+
+        public override int FieldSize
+        {
+            get { return Q.BitLength; }
+        }
+
+        public override ECFieldElement Add(ECFieldElement b)
+        {
+            uint[] z = Nat256.Create();
+            SM2P256V1Field.Add(x, ((SM2P256V1FieldElement)b).x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        public override ECFieldElement AddOne()
+        {
+            uint[] z = Nat256.Create();
+            SM2P256V1Field.AddOne(x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        public override ECFieldElement Subtract(ECFieldElement b)
+        {
+            uint[] z = Nat256.Create();
+            SM2P256V1Field.Subtract(x, ((SM2P256V1FieldElement)b).x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        public override ECFieldElement Multiply(ECFieldElement b)
+        {
+            uint[] z = Nat256.Create();
+            SM2P256V1Field.Multiply(x, ((SM2P256V1FieldElement)b).x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        public override ECFieldElement Divide(ECFieldElement b)
+        {
+            //return Multiply(b.Invert());
+            uint[] z = Nat256.Create();
+            Mod.Invert(SM2P256V1Field.P, ((SM2P256V1FieldElement)b).x, z);
+            SM2P256V1Field.Multiply(z, x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        public override ECFieldElement Negate()
+        {
+            uint[] z = Nat256.Create();
+            SM2P256V1Field.Negate(x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        public override ECFieldElement Square()
+        {
+            uint[] z = Nat256.Create();
+            SM2P256V1Field.Square(x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        public override ECFieldElement Invert()
+        {
+            //return new SM2P256V1FieldElement(ToBigInteger().ModInverse(Q));
+            uint[] z = Nat256.Create();
+            Mod.Invert(SM2P256V1Field.P, x, z);
+            return new SM2P256V1FieldElement(z);
+        }
+
+        /**
+         * return a sqrt root - the routine verifies that the calculation returns the right value - if
+         * none exists it returns null.
+         */
+        public override ECFieldElement Sqrt()
+        {
+            /*
+             * Raise this element to the exponent 2^254 - 2^222 - 2^94 + 2^62
+             *
+             * Breaking up the exponent's binary representation into "repunits", we get:
+             * { 31 1s } { 1 0s } { 128 1s } { 31 0s } { 1 1s } { 62 0s}
+             *
+             * We use an addition chain for the beginning: [1], 2, 3, 6, 12, [24], 30, [31] 
+             */
+
+            uint[] x1 = this.x;
+            if (Nat256.IsZero(x1) || Nat256.IsOne(x1))
+            {
+                return this;
+            }
+
+            uint[] x2 = Nat256.Create();
+            SM2P256V1Field.Square(x1, x2);
+            SM2P256V1Field.Multiply(x2, x1, x2);
+            uint[] x3 = x2;
+            SM2P256V1Field.Square(x2, x3);
+            SM2P256V1Field.Multiply(x3, x1, x3);
+            uint[] x6 = Nat256.Create();
+            SM2P256V1Field.SquareN(x3, 3, x6);
+            SM2P256V1Field.Multiply(x6, x3, x6);
+            uint[] x12 = x3;
+            SM2P256V1Field.SquareN(x6, 6, x12);
+            SM2P256V1Field.Multiply(x12, x6, x12);
+            uint[] x24 = Nat256.Create();
+            SM2P256V1Field.SquareN(x12, 12, x24);
+            SM2P256V1Field.Multiply(x24, x12, x24);
+            uint[] x30 = x12;
+            SM2P256V1Field.SquareN(x24, 6, x30);
+            SM2P256V1Field.Multiply(x30, x6, x30);
+            uint[] x31 = x6;
+            SM2P256V1Field.Square(x30, x31);
+            SM2P256V1Field.Multiply(x31, x1, x31);
+
+            uint[] t1 = x31;
+            SM2P256V1Field.Square(x31, t1);
+
+            uint[] x32 = x12;
+            SM2P256V1Field.Multiply(t1, x1, x32);
+
+            SM2P256V1Field.SquareN(t1, 32, t1);
+            SM2P256V1Field.Multiply(t1, x32, t1);
+
+            uint[] t2 = x24;
+            SM2P256V1Field.SquareN(t1, 32, t2);
+            SM2P256V1Field.Multiply(t2, x1, t2);
+            SM2P256V1Field.SquareN(t2, 32, t2);
+            SM2P256V1Field.Multiply(t2, t1, t2);
+            SM2P256V1Field.SquareN(t2, 32, t2);
+            SM2P256V1Field.Multiply(t2, x32, t2);
+            SM2P256V1Field.SquareN(t2, 32, t2);
+            SM2P256V1Field.Multiply(t2, x1, t2);
+            SM2P256V1Field.SquareN(t2, 62, t1);
+            SM2P256V1Field.Square(t1, t2);
+
+            return Nat256.Eq(x1, t2) ? new SM2P256V1FieldElement(t1) : null;
+        }
+
+        public override bool Equals(object obj)
+        {
+            return Equals(obj as SM2P256V1FieldElement);
+        }
+
+        public override bool Equals(ECFieldElement other)
+        {
+            return Equals(other as SM2P256V1FieldElement);
+        }
+
+        public virtual bool Equals(SM2P256V1FieldElement other)
+        {
+            if (this == other)
+                return true;
+            if (null == other)
+                return false;
+            return Nat256.Eq(x, other.x);
+        }
+
+        public override int GetHashCode()
+        {
+            return Q.GetHashCode() ^ Arrays.GetHashCode(x, 0, 8);
+        }
+    }
+}