Add a comparing service

Author: Coding-Enthusiast

Src/FinderOuter/Services/AddressService.cs

@@ -0,0 +1,32 @@
+// The FinderOuter
+// Copyright (c) 2020 Coding Enthusiast
+// Distributed under the MIT software license, see the accompanying
+// file LICENCE or http://www.opensource.org/licenses/mit-license.php.
+
+using Autarkysoft.Bitcoin.Blockchain.Scripts;
+using Autarkysoft.Bitcoin.Encoders;
+
+namespace FinderOuter.Services
+{
+    public class AddressService
+    {
+        private readonly Address addrMan = new Address();
+
+        public bool CheckAndGetHash(string address, out byte[] hash)
+        {
+            hash = null;
+            if (string.IsNullOrWhiteSpace(address))
+            {
+                return false;
+            }
+
+            return (address[0]) switch
+            {
+                '1' => addrMan.VerifyType(address, PubkeyScriptType.P2PKH, out hash),
+                '3' => addrMan.VerifyType(address, PubkeyScriptType.P2SH, out hash),
+                'b' => addrMan.VerifyType(address, PubkeyScriptType.P2WPKH, out hash),
+                _ => false,
+            };
+        }
+    }
+}

Src/FinderOuter/Services/ICompareService.cs

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+// The FinderOuter
+// Copyright (c) 2020 Coding Enthusiast
+// Distributed under the MIT software license, see the accompanying
+// file LICENCE or http://www.opensource.org/licenses/mit-license.php.
+
+namespace FinderOuter.Services
+{
+    public interface ICompareService
+    {
+        bool Compare(byte[] key);
+    }
+}

Src/FinderOuter/Services/PrivateKeyToAddressComparer.cs

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+// The FinderOuter
+// Copyright (c) 2020 Coding Enthusiast
+// Distributed under the MIT software license, see the accompanying
+// file LICENCE or http://www.opensource.org/licenses/mit-license.php.
+
+using Autarkysoft.Bitcoin.Cryptography.Asymmetric.EllipticCurve;
+using FinderOuter.Backend.Cryptography.Hashing;
+using System;
+using System.Numerics;
+
+namespace FinderOuter.Services
+{
+    public class PrivateKeyToAddressComparer : ICompareService
+    {
+        private readonly SecP256k1 curve = new SecP256k1();
+        private readonly EllipticCurveCalculator calc = new EllipticCurveCalculator();
+        private byte[] hash;
+        private Ripemd160Sha256 hash160 = new Ripemd160Sha256();
+
+
+        public bool TrySetHash(string address)
+        {
+            AddressService serv = new AddressService();
+            return serv.CheckAndGetHash(address, out hash);
+        }
+
+
+        public bool Compare(byte[] key)
+        {
+            BigInteger kVal = new BigInteger(key, true, true);
+            if (kVal >= curve.N)
+            {
+                return false;
+            }
+
+            EllipticCurvePoint point = calc.MultiplyByG(kVal);
+
+            byte[] xBytes = point.X.ToByteArray(true, true);
+            byte[] toHash = new byte[65];
+            toHash[0] = point.Y.IsEven ? (byte)2 : (byte)3;
+            Buffer.BlockCopy(xBytes, 0, toHash, 33 - xBytes.Length, xBytes.Length);
+
+            ReadOnlySpan<byte> compHash = hash160.Compress33(toHash);
+            if (compHash.SequenceEqual(hash))
+            {
+                return true;
+            }
+
+            byte[] yBytes = point.Y.ToByteArray(true, true);
+            toHash[0] = 4;
+            Buffer.BlockCopy(yBytes, 0, toHash, 65 - yBytes.Length, yBytes.Length);
+
+            ReadOnlySpan<byte> uncompHash = hash160.Compress65(toHash);
+            if (uncompHash.SequenceEqual(hash))
+            {
+                return true;
+            }
+
+            return false;
+        }
+    }
+}