Drop DesCipher; Replace PKCS7Padding with BouncyCastle's implementation.

Author: scott-xu

README.md

@@ -121,7 +121,6 @@ The main types provided by this library are:
 Private keys in OpenSSL traditional PEM format can be encrypted using one of the following cipher methods:
 * DES-EDE3-CBC
 * DES-EDE3-CFB
-* DES-CBC
 * AES-128-CBC
 * AES-192-CBC
 * AES-256-CBC

src/Renci.SshNet/PrivateKeyFile.PKCS1.cs

@@ -54,9 +54,6 @@ public Key Parse()
                         case "DES-EDE3-CFB":
                             cipher = new CipherInfo(192, (key, iv) => new TripleDesCipher(key, iv, BlockCipherMode.CFB, pkcs7Padding: false));
                             break;
-                        case "DES-CBC":
-                            cipher = new CipherInfo(64, (key, iv) => new DesCipher(key, iv, BlockCipherMode.CBC, pkcs7Padding: true));
-                            break;
                         case "AES-128-CBC":
                             cipher = new CipherInfo(128, (key, iv) => new AesCipher(key, iv, BlockCipherMode.CBC, pkcs7Padding: true));
                             break;

src/Renci.SshNet/PrivateKeyFile.PuTTY.cs

@@ -111,7 +111,7 @@ public Key Parse()
                                 throw new SshException("PuTTY key file version " + _version + " is not supported");
                         }
 
-                        using (var cipher = new AesCipher(cipherKey, cipherIV, AesCipherMode.CBC, pkcs7Padding: false))
+                        using (var cipher = new AesCipher(cipherKey, cipherIV, BlockCipherMode.CBC, pkcs7Padding: false))
                         {
                             privateKey = cipher.Decrypt(_data);
                         }

src/Renci.SshNet/PrivateKeyFile.cs

@@ -48,9 +48,6 @@ namespace Renci.SshNet
     ///         <description>DES-EDE3-CFB</description>
     ///     </item>
     ///     <item>
-    ///         <description>DES-CBC</description>
-    ///     </item>
-    ///     <item>
     ///         <description>AES-128-CBC</description>
     ///     </item>
     ///     <item>

src/Renci.SshNet/Security/Cryptography/BlockCipher.cs

@@ -1,5 +1,7 @@
 using System;
 
+using Org.BouncyCastle.Crypto.Paddings;
+
 using Renci.SshNet.Common;
 using Renci.SshNet.Security.Cryptography.Ciphers;
 using Renci.SshNet.Security.Cryptography.Ciphers.Modes;
@@ -13,7 +15,7 @@ public abstract class BlockCipher : SymmetricCipher
     {
         private readonly CipherMode _mode;
 
-        private readonly CipherPadding _padding;
+        private readonly IBlockCipherPadding _padding;
 
         /// <summary>
         /// Gets the size of the block in bytes.
@@ -56,7 +58,7 @@ public byte BlockSize
         /// <param name="mode">Cipher mode.</param>
         /// <param name="padding">Cipher padding.</param>
         /// <exception cref="ArgumentNullException"><paramref name="key"/> is <see langword="null"/>.</exception>
-        protected BlockCipher(byte[] key, byte blockSize, CipherMode mode, CipherPadding padding)
+        protected BlockCipher(byte[] key, byte blockSize, CipherMode mode, IBlockCipherPadding padding)
             : base(key)
         {
             _blockSize = blockSize;
@@ -81,7 +83,9 @@ public override byte[] Encrypt(byte[] input, int offset, int length)
             if (_padding is not null)
             {
                 paddingLength = _blockSize - (length % _blockSize);
-                input = _padding.Pad(input, offset, length, paddingLength);
+                input = input.Take(offset, length);
+                Array.Resize(ref input, length + paddingLength);
+                _ = _padding.AddPadding(input, length);
                 length += paddingLength;
                 offset = 0;
             }

src/Renci.SshNet/Security/Cryptography/Ciphers/AesCipher.BlockImpl.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Security.Cryptography;
 
+using Org.BouncyCastle.Crypto.Paddings;
+
 namespace Renci.SshNet.Security.Cryptography.Ciphers
 {
     public partial class AesCipher
@@ -11,7 +13,7 @@ private sealed class BlockImpl : BlockCipher, IDisposable
             private readonly ICryptoTransform _encryptor;
             private readonly ICryptoTransform _decryptor;
 
-            public BlockImpl(byte[] key, CipherMode mode, CipherPadding padding)
+            public BlockImpl(byte[] key, CipherMode mode, IBlockCipherPadding padding)
                 : base(key, 16, mode, padding)
             {
                 var aes = Aes.Create();

src/Renci.SshNet/Security/Cryptography/Ciphers/AesCipher.cs

@@ -1,8 +1,9 @@
 using System;
 using System.Security.Cryptography;
 
+using Org.BouncyCastle.Crypto.Paddings;
+
 using Renci.SshNet.Security.Cryptography.Ciphers.Modes;
-using Renci.SshNet.Security.Cryptography.Ciphers.Paddings;
 
 namespace Renci.SshNet.Security.Cryptography.Ciphers
 {
@@ -28,13 +29,13 @@ public AesCipher(byte[] key, byte[] iv, BlockCipherMode mode, bool pkcs7Padding
             if (mode == BlockCipherMode.OFB)
             {
                 // OFB is not supported on modern .NET
-                _impl = new BlockImpl(key, new OfbCipherMode(iv), pkcs7Padding ? new PKCS7Padding() : null);
+                _impl = new BlockImpl(key, new OfbCipherMode(iv), pkcs7Padding ? new Pkcs7Padding() : null);
             }
 #if !NET6_0_OR_GREATER
             else if (mode == BlockCipherMode.CFB)
             {
                 // CFB not supported on NetStandard 2.1
-                _impl = new BlockImpl(key, new CfbCipherMode(iv), pkcs7Padding ? new PKCS7Padding() : null);
+                _impl = new BlockImpl(key, new CfbCipherMode(iv), pkcs7Padding ? new Pkcs7Padding() : null);
             }
 #endif
             else if (mode == BlockCipherMode.CTR)