Replace the obsolete SecP256k1 curve object with a constant biginteger (curve order is the only prop used)

Author: Coding-Enthusiast

Src/FinderOuter/Backend/ConstantsFO.cs

@@ -4,6 +4,7 @@
 // file LICENCE or http://www.opensource.org/licenses/mit-license.php.
 
 using System;
+using System.Numerics;
 
 namespace FinderOuter.Backend
 {
@@ -71,5 +72,10 @@ public struct ConstantsFO
             ['X', 'x'],
             ['Z', 'z'],
         ];
+
+        /// <summary>
+        /// N = FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
+        /// </summary>
+        public static readonly BigInteger CurveOrder = BigInteger.Parse("115792089237316195423570985008687907852837564279074904382605163141518161494337");
     }
 }

Src/FinderOuter/Services/ArmoryService.cs

@@ -4,7 +4,6 @@
 // file LICENCE or http://www.opensource.org/licenses/mit-license.php.
 
 using Autarkysoft.Bitcoin;
-using Autarkysoft.Bitcoin.Cryptography.Asymmetric.EllipticCurve;
 using Autarkysoft.Bitcoin.Cryptography.EllipticCurve;
 using Autarkysoft.Bitcoin.Cryptography.EllipticCurve.Primitives;
 using FinderOuter.Backend;
@@ -37,7 +36,6 @@ public ArmoryService(IReport rep)
         private int[] missingIndexes;
         private bool hasChainCode;
         private byte[] chainCode;
-        private readonly BigInteger N = new SecP256k1().N;
 
 
 

Src/FinderOuter/Services/Base58Service.cs

@@ -142,8 +142,7 @@ private void WifLoopMissingEnd(bool compressed)
             BigInteger diff = end - start + 1;
             report.AddMessageSafe($"Using an optimized method checking only {diff:n0} keys.");
 
-            Autarkysoft.Bitcoin.Cryptography.Asymmetric.EllipticCurve.SecP256k1 curve = new();
-            if (start == 0 || end >= curve.N)
+            if (start == 0 || end >= ConstantsFO.CurveOrder)
             {
                 report.AddMessageSafe("There is something wrong with the given key, it is outside of valid key range.");
                 return;