Optimize BigInteger (neo-project#1280)

Tommo-L · Jun 22, 2020 · 0be3125 · 0be3125
1 parent c6629b7
commit 0be3125
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Showing 4 changed files with 14 additions and 18 deletions.
diff --git a/src/neo/Cryptography/Base58.cs b/src/neo/Cryptography/Base58.cs
@@ -25,16 +25,15 @@ public static byte[] Decode(string input)
             // Leading zero bytes get encoded as leading `1` characters
             int leadingZeroCount = input.TakeWhile(c => c == Alphabet[0]).Count();
             var leadingZeros = new byte[leadingZeroCount];
-            var bytesWithoutLeadingZeros = bi.ToByteArray()
-                .Reverse()// to big endian
-                .SkipWhile(b => b == 0);//strip sign byte
+            if (bi.IsZero) return leadingZeros;
+            var bytesWithoutLeadingZeros = bi.ToByteArray(isUnsigned: true, isBigEndian: true);
             return leadingZeros.Concat(bytesWithoutLeadingZeros).ToArray();
         }
 
         public static string Encode(byte[] input)
         {
             // Decode byte[] to BigInteger
-            BigInteger value = new BigInteger(new byte[1].Concat(input).Reverse().ToArray());
+            BigInteger value = new BigInteger(input, isUnsigned: true, isBigEndian: true);
 
             // Encode BigInteger to Base58 string
             var sb = new StringBuilder();

diff --git a/src/neo/Cryptography/ECC/ECDsa.cs b/src/neo/Cryptography/ECC/ECDsa.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Linq;
 using System.Numerics;
 using System.Security.Cryptography;
 
@@ -26,7 +25,7 @@ public ECDsa(ECPoint publicKey)
         private BigInteger CalculateE(BigInteger n, byte[] message)
         {
             int messageBitLength = message.Length * 8;
-            BigInteger trunc = new BigInteger(message.Reverse().Concat(new byte[1]).ToArray());
+            BigInteger trunc = new BigInteger(message, isUnsigned: true, isBigEndian: true);
             if (n.GetBitLength() < messageBitLength)
             {
                 trunc >>= messageBitLength - n.GetBitLength();
@@ -38,7 +37,7 @@ public BigInteger[] GenerateSignature(byte[] message)
         {
             if (privateKey == null) throw new InvalidOperationException();
             BigInteger e = CalculateE(curve.N, message);
-            BigInteger d = new BigInteger(privateKey.Reverse().Concat(new byte[1]).ToArray());
+            BigInteger d = new BigInteger(privateKey, isUnsigned: true, isBigEndian: true);
             BigInteger r, s;
             using (RandomNumberGenerator rng = RandomNumberGenerator.Create())
             {

diff --git a/src/neo/Cryptography/ECC/ECFieldElement.cs b/src/neo/Cryptography/ECC/ECFieldElement.cs
@@ -142,12 +142,10 @@ public ECFieldElement Square()
 
         public byte[] ToByteArray()
         {
-            byte[] data = Value.ToByteArray();
+            byte[] data = Value.ToByteArray(isUnsigned: true, isBigEndian: true);
             if (data.Length == 32)
-                return data.Reverse().ToArray();
-            if (data.Length > 32)
-                return data.Take(32).Reverse().ToArray();
-            return Enumerable.Repeat<byte>(0, 32 - data.Length).Concat(data.Reverse()).ToArray();
+                return data;
+            return Enumerable.Repeat<byte>(0, 32 - data.Length).Concat(data).ToArray();
         }
 
         public static ECFieldElement operator -(ECFieldElement x)

diff --git a/src/neo/Cryptography/ECC/ECPoint.cs b/src/neo/Cryptography/ECC/ECPoint.cs
@@ -52,16 +52,16 @@ public static ECPoint DecodePoint(byte[] encoded, ECCurve curve)
                         if (encoded.Length != (expectedLength + 1))
                             throw new FormatException("Incorrect length for compressed encoding");
                         int yTilde = encoded[0] & 1;
-                        BigInteger X1 = new BigInteger(encoded.Skip(1).Reverse().Concat(new byte[1]).ToArray());
+                        BigInteger X1 = new BigInteger(encoded.AsSpan(1), isUnsigned: true, isBigEndian: true);
                         p = DecompressPoint(yTilde, X1, curve);
                         break;
                     }
                 case 0x04: // uncompressed
                     {
                         if (encoded.Length != (2 * expectedLength + 1))
                             throw new FormatException("Incorrect length for uncompressed/hybrid encoding");
-                        BigInteger X1 = new BigInteger(encoded.Skip(1).Take(expectedLength).Reverse().Concat(new byte[1]).ToArray());
-                        BigInteger Y1 = new BigInteger(encoded.Skip(1 + expectedLength).Reverse().Concat(new byte[1]).ToArray());
+                        BigInteger X1 = new BigInteger(encoded.AsSpan(1, expectedLength), isUnsigned: true, isBigEndian: true);
+                        BigInteger Y1 = new BigInteger(encoded.AsSpan(1 + expectedLength), isUnsigned: true, isBigEndian: true);
                         p = new ECPoint(new ECFieldElement(X1, curve), new ECFieldElement(Y1, curve), curve);
                         break;
                     }
@@ -143,10 +143,10 @@ public byte[] EncodePoint(bool commpressed)
             else
             {
                 data = new byte[65];
-                byte[] yBytes = Y.Value.ToByteArray().Reverse().ToArray();
+                byte[] yBytes = Y.Value.ToByteArray(isUnsigned: true, isBigEndian: true);
                 Buffer.BlockCopy(yBytes, 0, data, 65 - yBytes.Length, yBytes.Length);
             }
-            byte[] xBytes = X.Value.ToByteArray().Reverse().ToArray();
+            byte[] xBytes = X.Value.ToByteArray(isUnsigned: true, isBigEndian: true);
             Buffer.BlockCopy(xBytes, 0, data, 33 - xBytes.Length, xBytes.Length);
             data[0] = commpressed ? Y.Value.IsEven ? (byte)0x02 : (byte)0x03 : (byte)0x04;
             return data;
@@ -379,7 +379,7 @@ private static sbyte[] WindowNaf(sbyte width, BigInteger k)
                 throw new ArgumentException();
             if (p.IsInfinity)
                 return p;
-            BigInteger k = new BigInteger(n.Reverse().Concat(new byte[1]).ToArray());
+            BigInteger k = new BigInteger(n, isUnsigned: true, isBigEndian: true);
             if (k.Sign == 0)
                 return p.Curve.Infinity;
             return Multiply(p, k);