NistPrimeCurve.cs

using System;
using System.IO;
using System.Numerics;
 
namespace Waher.Security.EllipticCurves
{
    public abstract class NistPrimeCurve : WeierstrassCurve
    {
        public NistPrimeCurve(BigInteger Prime, PointOnCurve BasePoint, BigInteger Order)
            : base(Prime, BasePoint, -3, Order, 1)
        {
        }
 
        public NistPrimeCurve(BigInteger Prime, PointOnCurve BasePoint, BigInteger Order,
            byte[] Secret)
            : base(Prime, BasePoint, -3, Order, 1, Secret)
        {
        }
 
        protected static BigInteger ToBigInteger(uint[] BigEndianDWords)
        {
            int i, c = BigEndianDWords.Length;
            int j = c << 2;
            byte[] B = new byte[((BigEndianDWords[0] & 0x80000000) != 0) ? j + 1 : j];
            uint k;
 
            for (i = 0; i < c; i++)
            {
                k = BigEndianDWords[i];
 
                B[j - 4] = (byte)k;
                k >>= 8;
                B[j - 3] = (byte)k;
                k >>= 8;
                B[j - 2] = (byte)k;
                k >>= 8;
                B[j - 1] = (byte)k;
 
                j -= 4;
            }
 
            return ToInt(B);
        }
 
        public virtual HashFunction HashFunction => HashFunction.SHA256;
 
        public override byte[] Sign(byte[] Data)
        {
            return ECDSA.Sign(Data, this.PrivateKey, 
                Bin => Hashes.ComputeHash(this.HashFunction, Bin),
                this.orderBytes, this.msbOrderMask, this);
        }
 
        public override byte[] Sign(Stream Data)
        {
            return ECDSA.Sign(Data, this.PrivateKey,
                Bin => Hashes.ComputeHash(this.HashFunction, Bin),
                this.orderBytes, this.msbOrderMask, this);
        }
 
        public override bool Verify(byte[] Data, byte[] PublicKey, byte[] Signature)
        {
            return ECDSA.Verify(Data, PublicKey,
                Bin => Hashes.ComputeHash(this.HashFunction, Bin),
                this.orderBytes, this.msbOrderMask, this, Signature);
        }
 
        public override bool Verify(Stream Data, byte[] PublicKey, byte[] Signature)
        {
            return ECDSA.Verify(Data, PublicKey,
                Bin => Hashes.ComputeHash(this.HashFunction, Bin),
                this.orderBytes, this.msbOrderMask, this, Signature);
        }
 
    }
}