diff --git a/shadowsocks-csharp/Encryption/EncryptorFactory.cs b/shadowsocks-csharp/Encryption/EncryptorFactory.cs
index 7e1d6264..08e234d9 100644
--- a/shadowsocks-csharp/Encryption/EncryptorFactory.cs
+++ b/shadowsocks-csharp/Encryption/EncryptorFactory.cs
@@ -26,7 +26,7 @@ namespace Shadowsocks.Encryption
             {
                 AEADSodiumEncryptorSupportedCiphers.Remove("aes-256-gcm");
             }
-
+#if I_KNOW_STREAM_CIPHER_IS_UNSAFE
             // XXX: sequence matters, OpenSSL > Sodium > MbedTLS
             foreach (string method in StreamOpenSSLEncryptor.SupportedCiphers())
             {
@@ -45,8 +45,8 @@ namespace Shadowsocks.Encryption
                 if (!_registeredEncryptors.ContainsKey(method))
                     _registeredEncryptors.Add(method, typeof(StreamMbedTLSEncryptor));
             }
-
-
+#endif
+    
             foreach (string method in AEADOpenSSLEncryptor.SupportedCiphers())
             {
                 if (!_registeredEncryptors.ContainsKey(method))
@@ -97,4 +97,4 @@ namespace Shadowsocks.Encryption
             return sb.ToString();
         }
     }
-}
\ No newline at end of file
+}
diff --git a/test/CryptographyTest.cs b/test/CryptographyTest.cs
deleted file mode 100644
index 68c2e3a8..00000000
--- a/test/CryptographyTest.cs
+++ /dev/null
@@ -1,233 +0,0 @@
-using System;
-using Microsoft.VisualStudio.TestTools.UnitTesting;
-using Shadowsocks.Encryption;
-using System.Threading;
-using System.Collections.Generic;
-using Shadowsocks.Encryption.Stream;
-using System.Diagnostics;
-
-namespace Shadowsocks.Test
-{
-    [TestClass]
-    public class CryptographyTest
-    {
-
-        [TestMethod]
-        public void TestMD5()
-        {
-            for (int len = 1; len < 64; len++)
-            {
-                System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
-                byte[] bytes = new byte[len];
-                var random = new Random();
-                random.NextBytes(bytes);
-                string md5str = Convert.ToBase64String(md5.ComputeHash(bytes));
-                string md5str2 = Convert.ToBase64String(MbedTLS.MD5(bytes));
-                Assert.IsTrue(md5str == md5str2);
-            }
-        }
-
-        private void RunEncryptionRound(IEncryptor encryptor, IEncryptor decryptor)
-        {
-            RNG.Reload();
-            byte[] plain = new byte[16384];
-            byte[] cipher = new byte[plain.Length + 16];
-            byte[] plain2 = new byte[plain.Length + 16];
-            int outLen = 0;
-            int outLen2 = 0;
-            var random = new Random();
-            random.NextBytes(plain);
-            encryptor.Encrypt(plain, plain.Length, cipher, out outLen);
-            decryptor.Decrypt(cipher, outLen, plain2, out outLen2);
-            Assert.AreEqual(plain.Length, outLen2);
-            for (int j = 0; j < plain.Length; j++)
-            {
-                Assert.AreEqual(plain[j], plain2[j]);
-            }
-            encryptor.Encrypt(plain, 1000, cipher, out outLen);
-            decryptor.Decrypt(cipher, outLen, plain2, out outLen2);
-            Assert.AreEqual(1000, outLen2);
-            for (int j = 0; j < outLen2; j++)
-            {
-                Assert.AreEqual(plain[j], plain2[j]);
-            }
-            encryptor.Encrypt(plain, 12333, cipher, out outLen);
-            decryptor.Decrypt(cipher, outLen, plain2, out outLen2);
-            Assert.AreEqual(12333, outLen2);
-            for (int j = 0; j < outLen2; j++)
-            {
-                Assert.AreEqual(plain[j], plain2[j]);
-            }
-        }
-
-        private static bool encryptionFailed = false;
-        private static object locker = new object();
-
-        [TestMethod]
-        public void TestMbedTLSEncryption()
-        {
-            encryptionFailed = false;
-            // run it once before the multi-threading test to initialize global tables
-            RunSingleMbedTLSEncryptionThread();
-            List<Thread> threads = new List<Thread>();
-            for (int i = 0; i < 10; i++)
-            {
-                Thread t = new Thread(new ThreadStart(RunSingleMbedTLSEncryptionThread));
-                threads.Add(t);
-                t.Start();
-            }
-            foreach (Thread t in threads)
-            {
-                t.Join();
-            }
-            RNG.Close();
-            Assert.IsFalse(encryptionFailed);
-        }
-
-        private void RunSingleMbedTLSEncryptionThread()
-        {
-            try
-            {
-                for (int i = 0; i < 100; i++)
-                {
-                    IEncryptor encryptor;
-                    IEncryptor decryptor;
-                    encryptor = new StreamMbedTLSEncryptor("aes-256-cfb", "barfoo!");
-                    decryptor = new StreamMbedTLSEncryptor("aes-256-cfb", "barfoo!");
-                    RunEncryptionRound(encryptor, decryptor);
-                }
-            }
-            catch
-            {
-                encryptionFailed = true;
-                throw;
-            }
-        }
-
-        [TestMethod]
-        public void TestRC4Encryption()
-        {
-            encryptionFailed = false;
-            // run it once before the multi-threading test to initialize global tables
-            RunSingleRC4EncryptionThread();
-            List<Thread> threads = new List<Thread>();
-            for (int i = 0; i < 10; i++)
-            {
-                Thread t = new Thread(new ThreadStart(RunSingleRC4EncryptionThread));
-                threads.Add(t);
-                t.Start();
-            }
-            foreach (Thread t in threads)
-            {
-                t.Join();
-            }
-            RNG.Close();
-            Assert.IsFalse(encryptionFailed);
-        }
-
-        private void RunSingleRC4EncryptionThread()
-        {
-            try
-            {
-                for (int i = 0; i < 100; i++)
-                {
-                    var random = new Random();
-                    IEncryptor encryptor;
-                    IEncryptor decryptor;
-                    encryptor = new StreamMbedTLSEncryptor("rc4-md5", "barfoo!");
-                    decryptor = new StreamMbedTLSEncryptor("rc4-md5", "barfoo!");
-                    RunEncryptionRound(encryptor, decryptor);
-                }
-            }
-            catch
-            {
-                encryptionFailed = true;
-                throw;
-            }
-        }
-
-        [TestMethod]
-        public void TestSodiumEncryption()
-        {
-            encryptionFailed = false;
-            // run it once before the multi-threading test to initialize global tables
-            RunSingleSodiumEncryptionThread();
-            List<Thread> threads = new List<Thread>();
-            for (int i = 0; i < 10; i++)
-            {
-                Thread t = new Thread(new ThreadStart(RunSingleSodiumEncryptionThread));
-                threads.Add(t);
-                t.Start();
-            }
-            foreach (Thread t in threads)
-            {
-                t.Join();
-            }
-            RNG.Close();
-            Assert.IsFalse(encryptionFailed);
-        }
-
-        private void RunSingleSodiumEncryptionThread()
-        {
-            try
-            {
-                for (int i = 0; i < 100; i++)
-                {
-                    var random = new Random();
-                    IEncryptor encryptor;
-                    IEncryptor decryptor;
-                    encryptor = new StreamSodiumEncryptor("salsa20", "barfoo!");
-                    decryptor = new StreamSodiumEncryptor("salsa20", "barfoo!");
-                    RunEncryptionRound(encryptor, decryptor);
-                }
-            }
-            catch
-            {
-                encryptionFailed = true;
-                throw;
-            }
-        }
-
-        [TestMethod]
-        public void TestOpenSSLEncryption()
-        {
-            encryptionFailed = false;
-            // run it once before the multi-threading test to initialize global tables
-            RunSingleOpenSSLEncryptionThread();
-            List<Thread> threads = new List<Thread>();
-            for (int i = 0; i < 10; i++)
-            {
-                Thread t = new Thread(new ThreadStart(RunSingleOpenSSLEncryptionThread));
-                threads.Add(t);
-                t.Start();
-            }
-            foreach (Thread t in threads)
-            {
-                t.Join();
-            }
-            RNG.Close();
-            Assert.IsFalse(encryptionFailed);
-        }
-
-        private void RunSingleOpenSSLEncryptionThread()
-        {
-            try
-            {
-                for (int i = 0; i < 100; i++)
-                {
-                    var random = new Random();
-                    IEncryptor encryptor;
-                    IEncryptor decryptor;
-                    encryptor = new StreamOpenSSLEncryptor("aes-256-cfb", "barfoo!");
-                    decryptor = new StreamOpenSSLEncryptor("aes-256-cfb", "barfoo!");
-                    RunEncryptionRound(encryptor, decryptor);
-                }
-            }
-            catch
-            {
-                encryptionFailed = true;
-                throw;
-            }
-        }
-    }
-}
diff --git a/test/ShadowsocksTest.csproj b/test/ShadowsocksTest.csproj
index 4cc9932f..54c1b19f 100644
--- a/test/ShadowsocksTest.csproj
+++ b/test/ShadowsocksTest.csproj
@@ -56,7 +56,7 @@
   </Choose>
   <ItemGroup>
     <Compile Include="ProcessEnvironment.cs" />
-    <Compile Include="CryptographyTest.cs" />
+    
     <Compile Include="Sip003PluginTest.cs" />
     <Compile Include="UrlTest.cs" />
     <Compile Include="UnitTest.cs" />
@@ -99,4 +99,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
\ No newline at end of file
+</Project>