From 7ea2e9e5c2d7725302cb0f8fbb3c1d3f2e0a90a8 Mon Sep 17 00:00:00 2001
From: clowwindy <clowwindy42@gmail.com>
Date: Sun, 2 Nov 2014 19:39:08 +0800
Subject: [PATCH] add rc4-md5

---
 shadowsocks-csharp/Encrypt/OpenSSL.cs         |  3 +-
 .../Encrypt/OpensslEncryptor.cs               | 30 ++++++++++++++++---
 shadowsocks-csharp/shadowsocks-csharp.csproj  |  2 +-
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/shadowsocks-csharp/Encrypt/OpenSSL.cs b/shadowsocks-csharp/Encrypt/OpenSSL.cs
index 53d65ac7..5afa374b 100755
--- a/shadowsocks-csharp/Encrypt/OpenSSL.cs
+++ b/shadowsocks-csharp/Encrypt/OpenSSL.cs
@@ -39,6 +39,7 @@ namespace shadowsocks_csharp.Encrypt
         [DllImport(DLLNAME, CallingConvention = CallingConvention.Cdecl)]
         public extern static int EVP_CipherUpdate(IntPtr ctx, byte[] outb, out int outl, byte[] inb, int inl);
 
-
+        [DllImport(DLLNAME, CallingConvention = CallingConvention.Cdecl)]
+        public extern static IntPtr MD5(byte[] d, long n, byte[] md);
     }
 }
diff --git a/shadowsocks-csharp/Encrypt/OpensslEncryptor.cs b/shadowsocks-csharp/Encrypt/OpensslEncryptor.cs
index 5645a934..d8548f4f 100644
--- a/shadowsocks-csharp/Encrypt/OpensslEncryptor.cs
+++ b/shadowsocks-csharp/Encrypt/OpensslEncryptor.cs
@@ -13,7 +13,8 @@ namespace shadowsocks_csharp.Encrypt
             {"aes-192-cfb", new int[]{24, 16}},
             {"aes-256-cfb", new int[]{32, 16}},
             {"bf-cfb", new int[]{16, 8}},
-            {"rc4", new int[]{16, 0}},
+            {"rc4", new int[]{16, 0}},
+            {"rc4-md5", new int[]{16, 16}},
         };
 
         static OpensslEncryptor()
@@ -86,20 +87,26 @@ namespace shadowsocks_csharp.Encrypt
         private IntPtr _encryptCtx;
         private IntPtr _decryptCtx;
         private IntPtr _cipher;
+        private string _method;
         private int keyLen;
         private int ivLen;
 
         private void InitKey(string method, string password)
         {
             method = method.ToLower();
+            _method = method;
             string k = method + ":" + password;
+            if (method == "rc4-md5")
+            {
+                method = "rc4";
+            }
             _cipher = OpenSSL.EVP_get_cipherbyname(System.Text.Encoding.UTF8.GetBytes(method));
             if (_cipher == null)
             {
                 throw new Exception("method not found");
             }
-            keyLen = ciphers[method][0];
-            ivLen = ciphers[method][1];
+            keyLen = ciphers[_method][0];
+            ivLen = ciphers[_method][1];
             if (CachedKeys.ContainsKey(k))
             {
                 _key = CachedKeys[k];
@@ -118,7 +125,22 @@ namespace shadowsocks_csharp.Encrypt
         {
             ctx = OpenSSL.EVP_CIPHER_CTX_new();
             int enc = isCipher ? 1 : 0;
-            OpenSSL.EVP_CipherInit_ex(ctx, _cipher, IntPtr.Zero, _key, iv, enc);
+            byte[] realkey;
+            IntPtr r = IntPtr.Zero;
+            if (_method == "rc4-md5")
+            {
+                byte[] temp = new byte[keyLen + ivLen];
+                realkey = new byte[keyLen];
+                Array.Copy(_key, 0, temp, 0, keyLen);
+                Array.Copy(iv, 0, temp, keyLen, ivLen);
+                r = OpenSSL.MD5(temp, keyLen + ivLen, null);
+                Marshal.Copy(r, realkey, 0, keyLen);
+            }
+            else
+            {
+                realkey = _key;
+            }
+            OpenSSL.EVP_CipherInit_ex(ctx, _cipher, IntPtr.Zero, realkey, iv, enc);
         }
 
         #region IDisposable
diff --git a/shadowsocks-csharp/shadowsocks-csharp.csproj b/shadowsocks-csharp/shadowsocks-csharp.csproj
index 6c783b95..ab21e895 100755
--- a/shadowsocks-csharp/shadowsocks-csharp.csproj
+++ b/shadowsocks-csharp/shadowsocks-csharp.csproj
@@ -9,7 +9,7 @@
     <OutputType>WinExe</OutputType>
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>shadowsocks_csharp</RootNamespace>
-    <AssemblyName>shadowsocks-csharp</AssemblyName>
+    <AssemblyName>Shadowsocks</AssemblyName>
     <TargetFrameworkVersion>v2.0</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <StartupObject>