use extension members for Convert.To/FromHexString

Author: mus65

src/Renci.SshNet/Abstractions/ConvertExtensions.cs

@@ -0,0 +1,34 @@
+#nullable enable
+#if !NET
+using System.Text;
+#endif
+
+namespace System
+{
+    internal static class ConvertExtensions
+    {
+        extension(Convert)
+        {
+#if !NET
+            public static byte[] FromHexString(string s)
+            {
+                return Org.BouncyCastle.Utilities.Encoders.Hex.Decode(s);
+            }
+
+            public static string ToHexString(byte[] inArray)
+            {
+                ArgumentNullException.ThrowIfNull(inArray);
+
+                var builder = new StringBuilder(inArray.Length * 2);
+
+                foreach (var b in inArray)
+                {
+                    builder.Append(b.ToString("X2"));
+                }
+
+                return builder.ToString();
+            }
+#endif
+        }
+    }
+}

src/Renci.SshNet/PrivateKeyFile.PKCS1.cs

@@ -42,11 +42,8 @@ public Key Parse()
                     {
                         throw new SshPassPhraseNullOrEmptyException("Private key is encrypted but passphrase is empty.");
                     }
-#if NET
+
                     var binarySalt = Convert.FromHexString(_salt);
-#else
-                    var binarySalt = Org.BouncyCastle.Utilities.Encoders.Hex.Decode(_salt);
-#endif
                     CipherInfo cipher;
                     switch (_cipherName)
                     {

src/Renci.SshNet/PrivateKeyFile.PuTTY.cs

@@ -82,11 +82,7 @@ public Key Parse()
                                     Convert.ToInt32(_argon2Iterations),
                                     Convert.ToInt32(_argon2Memory),
                                     Convert.ToInt32(_argon2Parallelism),
-#if NET
                                     Convert.FromHexString(_argon2Salt),
-#else
-                                    Org.BouncyCastle.Utilities.Encoders.Hex.Decode(_argon2Salt),
-#endif
                                     _passPhrase);
 
                                 cipherKey = keyData.Take(32);
@@ -152,11 +148,9 @@ public Key Parse()
                 {
                     macValue = hmac.ComputeHash(macData);
                 }
-#if NET
+
                 var reference = Convert.FromHexString(_mac);
-#else
-                var reference = Org.BouncyCastle.Utilities.Encoders.Hex.Decode(_mac);
-#endif
+
                 if (!macValue.SequenceEqual(reference))
                 {
                     throw new SshException("MAC verification failed for PuTTY key file");

src/Renci.SshNet/Session.cs

@@ -5,9 +5,6 @@
 using System.Linq;
 using System.Net.Sockets;
 using System.Security.Cryptography;
-#if !NET
-using System.Text;
-#endif
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -310,7 +307,7 @@ public byte[] SessionId
             private set
             {
                 _sessionId = value;
-                SessionIdHex = ToHex(value);
+                SessionIdHex = value == null ? null : Convert.ToHexString(value);
             }
         }
 
@@ -1592,7 +1589,7 @@ internal void OnNewKeysReceived(NewKeysMessage message)
             {
                 System.IO.File.AppendAllText(
                     path,
-                    $"{ToHex(ClientInitMessage.Cookie)} SHARED_SECRET {ToHex(kex.SharedKey)}{Environment.NewLine}");
+                    $"{Convert.ToHexString(ClientInitMessage.Cookie)} SHARED_SECRET {Convert.ToHexString(kex.SharedKey)}{Environment.NewLine}");
             }
 #endif
 
@@ -1861,27 +1858,6 @@ private Message LoadMessage(byte[] data, int offset, int count)
             return message;
         }
 
-        private static string ToHex(byte[] bytes)
-        {
-            if (bytes is null)
-            {
-                return null;
-            }
-
-#if NET
-            return Convert.ToHexString(bytes);
-#else
-            var builder = new StringBuilder(bytes.Length * 2);
-
-            foreach (var b in bytes)
-            {
-                builder.Append(b.ToString("X2"));
-            }
-
-            return builder.ToString();
-#endif
-        }
-
         /// <summary>
         /// Gets a value indicating whether the socket is connected.
         /// </summary>

test/Renci.SshNet.Tests/Classes/Security/Cryptography/RsaKeyTest.cs

@@ -24,11 +24,7 @@ private static RsaKey GetRsaKey(string fileName, string passPhrase = null)
         // This is just to line up any differences in the assertion message.
         private static void AssertEqual(byte[] actualBytes, string expectedHex)
         {
-#if NET
             string actualHex = Convert.ToHexString(actualBytes);
-#else
-            string actualHex = BitConverter.ToString(actualBytes).Replace("-", "");
-#endif
 
             Assert.AreEqual(expectedHex, actualHex,
                 $"{Environment.NewLine}Expected: {expectedHex}{Environment.NewLine}  Actual: {actualHex}");