make compiler happy in encryption

shadowsocks-csharp/Encryption/AEAD/AEADAesGcmNativeEncryptor.cs

@@ -18,7 +18,7 @@ namespace Shadowsocks.Encryption.AEAD
             {"aes-256-gcm", new CipherInfo("aes-256-gcm", 32, 32, 12, 16, CipherFamily.AesGcm)},
         };
 
-        protected override Dictionary<string, CipherInfo> getCiphers()
+        protected override Dictionary<string, CipherInfo> GetCiphers()
         {
             return _ciphers;
         }
@@ -32,7 +32,7 @@ namespace Shadowsocks.Encryption.AEAD
         public override int CipherEncrypt(ReadOnlySpan<byte> plain, Span<byte> cipher)
         {
             using AesGcm aes = new AesGcm(sessionKey);
-            aes.Encrypt(nonce.AsSpan(), plain, cipher.Slice(0, plain.Length), cipher.Slice(plain.Length, tagLen));
+            aes.Encrypt(nonce, plain, cipher.Slice(0, plain.Length), cipher.Slice(plain.Length, tagLen));
             return plain.Length + tagLen;
         }
 
@@ -42,7 +42,7 @@ namespace Shadowsocks.Encryption.AEAD
             using AesGcm aes = new AesGcm(sessionKey);
             ReadOnlySpan<byte> ciphertxt = cipher.Slice(0, clen);
             ReadOnlySpan<byte> tag = cipher.Slice(clen);
-            aes.Decrypt(nonce.AsSpan(), ciphertxt, tag, plain.Slice(0, clen));
+            aes.Decrypt(nonce, ciphertxt, tag, plain.Slice(0, clen));
             return clen;
         }
     }

shadowsocks-csharp/Encryption/AEAD/AEADEncryptor.cs

@@ -5,26 +5,25 @@ using Shadowsocks.Encryption.Stream;
 using System;
 using System.Collections.Generic;
 using System.Net;
+using System.Runtime.CompilerServices;
 using System.Text;
 
 namespace Shadowsocks.Encryption.AEAD
 {
     public abstract class AEADEncryptor : EncryptorBase
     {
-        private static Logger logger = LogManager.GetCurrentClassLogger();
+        private static readonly Logger logger = LogManager.GetCurrentClassLogger();
         // We are using the same saltLen and keyLen
         private const string Info = "ss-subkey";
         private static readonly byte[] InfoBytes = Encoding.ASCII.GetBytes(Info);
 
         // every connection should create its own buffer
-        private byte[] sharedBuffer = new byte[65536];
+        private readonly byte[] buffer = new byte[65536];
         private int bufPtr = 0;
 
         public const int ChunkLengthBytes = 2;
         public const uint ChunkLengthMask = 0x3FFFu;
 
-        protected Dictionary<string, CipherInfo> ciphers;
-
         protected CipherFamily cipherFamily;
         protected CipherInfo CipherInfo;
         protected static byte[] masterKey = Array.Empty<byte>();
@@ -46,7 +45,7 @@ namespace Shadowsocks.Encryption.AEAD
         public AEADEncryptor(string method, string password)
             : base(method, password)
         {
-            CipherInfo = getCiphers()[method.ToLower()];
+            CipherInfo = GetCiphers()[method.ToLower()];
             cipherFamily = CipherInfo.Type;
             AEADCipherParameter parameter = (AEADCipherParameter)CipherInfo.CipherParameter;
             keyLen = parameter.KeySize;
@@ -55,13 +54,15 @@ namespace Shadowsocks.Encryption.AEAD
             nonceLen = parameter.NonceSize;
 
             InitKey(password);
+
+            salt = new byte[saltLen];
             // Initialize all-zero nonce for each connection
             nonce = new byte[nonceLen];
             logger.Dump($"masterkey {instanceId}", masterKey, keyLen);
             logger.Dump($"nonce {instanceId}", nonce, keyLen);
         }
 
-        protected abstract Dictionary<string, CipherInfo> getCiphers();
+        protected abstract Dictionary<string, CipherInfo> GetCiphers();
 
         protected void InitKey(string password)
         {
@@ -77,32 +78,18 @@ namespace Shadowsocks.Encryption.AEAD
                 Array.Resize(ref masterKey, keyLen);
             }
 
-            DeriveKey(passbuf, masterKey, keyLen);
+            StreamEncryptor.LegacyDeriveKey(passbuf, masterKey, keyLen);
             // init session key
             sessionKey = new byte[keyLen];
         }
 
-        public void DeriveKey(byte[] password, byte[] key, int keylen)
-        {
-            StreamEncryptor.LegacyDeriveKey(password, key, keylen);
-        }
-
-        public void DeriveSessionKey(byte[] salt, byte[] masterKey, byte[] sessionKey)
-        {
-            CryptoUtils.HKDF(keyLen, masterKey, salt, InfoBytes).CopyTo(sessionKey, 0);
-        }
-
-        protected void IncrementNonce()
-        {
-            CryptoUtils.SodiumIncrement(nonce);
-        }
-
-        public virtual void InitCipher(byte[] salt, bool isEncrypt, bool isUdp)
+        public virtual void InitCipher(byte[] salt, bool isEncrypt)
         {
             this.salt = new byte[saltLen];
             Array.Copy(salt, this.salt, saltLen);
 
-            DeriveSessionKey(salt, masterKey, sessionKey);
+            CryptoUtils.HKDF(keyLen, masterKey, salt, InfoBytes).CopyTo(sessionKey, 0);
+
             logger.Dump($"salt {instanceId}", salt, saltLen);
             logger.Dump($"sessionkey {instanceId}", sessionKey, keyLen);
         }
@@ -112,10 +99,11 @@ namespace Shadowsocks.Encryption.AEAD
 
         #region TCP
 
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int Encrypt(ReadOnlySpan<byte> plain, Span<byte> cipher)
         {
             // push data
-            Span<byte> tmp = sharedBuffer.AsSpan(0, plain.Length + bufPtr);
+            Span<byte> tmp = buffer.AsSpan(0, plain.Length + bufPtr);
             plain.CopyTo(tmp.Slice(bufPtr));
 
             int outlength = 0;
@@ -124,7 +112,7 @@ namespace Shadowsocks.Encryption.AEAD
                 saltReady = true;
                 // Generate salt
                 byte[] saltBytes = RNG.GetBytes(saltLen);
-                InitCipher(saltBytes, true, false);
+                InitCipher(saltBytes, true);
                 saltBytes.CopyTo(cipher);
                 outlength = saltLen;
             }
@@ -162,7 +150,7 @@ namespace Shadowsocks.Encryption.AEAD
                     logger.Debug("enc outbuf almost full, giving up");
 
                     // write rest data to head of shared buffer
-                    tmp.CopyTo(sharedBuffer);
+                    tmp.CopyTo(buffer);
                     bufPtr = tmp.Length;
 
                     return outlength;
@@ -177,11 +165,12 @@ namespace Shadowsocks.Encryption.AEAD
             }
         }
 
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int Decrypt(Span<byte> plain, ReadOnlySpan<byte> cipher)
         {
             int outlength = 0;
             // drop all into buffer
-            Span<byte> tmp = sharedBuffer.AsSpan(0, cipher.Length + bufPtr);
+            Span<byte> tmp = buffer.AsSpan(0, cipher.Length + bufPtr);
             cipher.CopyTo(tmp.Slice(bufPtr));
             int bufSize = tmp.Length;
 
@@ -192,7 +181,7 @@ namespace Shadowsocks.Encryption.AEAD
                 if (bufSize <= saltLen)
                 {
                     // need more, write back cache
-                    tmp.CopyTo(sharedBuffer);
+                    tmp.CopyTo(buffer);
                     bufPtr = tmp.Length;
                     return outlength;
                 }
@@ -202,7 +191,7 @@ namespace Shadowsocks.Encryption.AEAD
                 byte[] salt = tmp.Slice(0, saltLen).ToArray();
                 tmp = tmp.Slice(saltLen);
 
-                InitCipher(salt, false, false);
+                InitCipher(salt, false);
                 logger.Debug("get salt len " + saltLen);
             }
 
@@ -222,7 +211,7 @@ namespace Shadowsocks.Encryption.AEAD
                 {
                     // so we only have chunk length and its tag?
                     // wait more
-                    tmp.CopyTo(sharedBuffer);
+                    tmp.CopyTo(buffer);
                     bufPtr = tmp.Length;
                     return outlength;
                 }
@@ -231,7 +220,7 @@ namespace Shadowsocks.Encryption.AEAD
                 if (len <= 0)
                 {
                     // no chunk decrypted
-                    tmp.CopyTo(sharedBuffer);
+                    tmp.CopyTo(buffer);
                     bufPtr = tmp.Length;
                     return outlength;
                 }
@@ -243,7 +232,7 @@ namespace Shadowsocks.Encryption.AEAD
                 if (outlength + 100 > TCPHandler.BufferSize)
                 {
                     logger.Debug("dec outbuf almost full, giving up");
-                    tmp.CopyTo(sharedBuffer);
+                    tmp.CopyTo(buffer);
                     bufPtr = tmp.Length;
                     return outlength;
                 }
@@ -260,21 +249,24 @@ namespace Shadowsocks.Encryption.AEAD
         #endregion
 
         #region UDP
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int EncryptUDP(ReadOnlySpan<byte> plain, Span<byte> cipher)
         {
             RNG.GetSpan(cipher.Slice(0, saltLen));
-            InitCipher(cipher.Slice(0, saltLen).ToArray(), true, true);
+            InitCipher(cipher.Slice(0, saltLen).ToArray(), true);
             return saltLen + CipherEncrypt(plain, cipher.Slice(saltLen));
         }
 
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int DecryptUDP(Span<byte> plain, ReadOnlySpan<byte> cipher)
         {
-            InitCipher(cipher.Slice(0, saltLen).ToArray(), false, true);
+            InitCipher(cipher.Slice(0, saltLen).ToArray(), false);
             return CipherDecrypt(plain, cipher.Slice(saltLen));
         }
 
         #endregion
 
+        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         private int ChunkEncrypt(ReadOnlySpan<byte> plain, Span<byte> cipher)
         {
             if (plain.Length > ChunkLengthMask)
@@ -285,13 +277,14 @@ namespace Shadowsocks.Encryption.AEAD
 
             byte[] lenbuf = BitConverter.GetBytes((ushort)IPAddress.HostToNetworkOrder((short)plain.Length));
             int cipherLenSize = CipherEncrypt(lenbuf, cipher);
-            IncrementNonce();
+            CryptoUtils.SodiumIncrement(nonce);
             int cipherDataSize = CipherEncrypt(plain, cipher.Slice(cipherLenSize));
-            IncrementNonce();
+            CryptoUtils.SodiumIncrement(nonce);
 
             return cipherLenSize + cipherDataSize;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         private int ChunkDecrypt(Span<byte> plain, ReadOnlySpan<byte> cipher)
         {
             // try to dec chunk len
@@ -311,11 +304,11 @@ namespace Shadowsocks.Encryption.AEAD
                 logger.Debug("No data to decrypt one chunk");
                 return 0;
             }
-            IncrementNonce();
+            CryptoUtils.SodiumIncrement(nonce);
             // we have enough data to decrypt one chunk
             // drop chunk len and its tag from buffer
             int len = CipherDecrypt(plain, cipher.Slice(ChunkLengthBytes + tagLen, chunkLength + tagLen));
-            IncrementNonce();
+            CryptoUtils.SodiumIncrement(nonce);
             return len;
         }
     }

shadowsocks-csharp/Encryption/AEAD/AEADNaClEncryptor.cs

@@ -8,7 +8,7 @@ namespace Shadowsocks.Encryption.AEAD
     public class AEADNaClEncryptor : AEADEncryptor
     {
 
-        SnufflePoly1305 enc;
+        SnufflePoly1305? enc;
         public AEADNaClEncryptor(string method, string password) : base(method, password)
         {
         }
@@ -20,7 +20,7 @@ namespace Shadowsocks.Encryption.AEAD
             {"xchacha20-ietf-poly1305", new CipherInfo("xchacha20-ietf-poly1305",32, 32, 24, 16, CipherFamily.XChacha20Poly1305)},
         };
 
-        protected override Dictionary<string, CipherInfo> getCiphers()
+        protected override Dictionary<string, CipherInfo> GetCiphers()
         {
             return _ciphers;
         }
@@ -31,31 +31,26 @@ namespace Shadowsocks.Encryption.AEAD
         }
         #endregion
 
-        public override void InitCipher(byte[] salt, bool isEncrypt, bool isUdp)
+        public override void InitCipher(byte[] salt, bool isEncrypt)
         {
-            base.InitCipher(salt, isEncrypt, isUdp);
-            switch (cipherFamily)
+            base.InitCipher(salt, isEncrypt);
+            enc = cipherFamily switch
             {
-                default:
-                case CipherFamily.Chacha20Poly1305:
-                    enc = new ChaCha20Poly1305(sessionKey);
-                    break;
-                case CipherFamily.XChacha20Poly1305:
-                    enc = new XChaCha20Poly1305(sessionKey);
-                    break;
-            }
+                CipherFamily.XChacha20Poly1305 => new XChaCha20Poly1305(sessionKey),
+                _ => new ChaCha20Poly1305(sessionKey),
+            };
         }
 
         public override int CipherEncrypt(ReadOnlySpan<byte> plain, Span<byte> cipher)
         {
-            byte[] ct = enc.Encrypt(plain, null, nonce);
+            byte[] ct = enc!.Encrypt(plain, null, nonce);
             ct.CopyTo(cipher);
             return ct.Length;
         }
 
         public override int CipherDecrypt(Span<byte> plain, ReadOnlySpan<byte> cipher)
         {
-            byte[] pt = enc.Decrypt(cipher, null, nonce);
+            byte[] pt = enc!.Decrypt(cipher, null, nonce);
             pt.CopyTo(plain);
             return pt.Length;
         }

shadowsocks-csharp/Encryption/EncryptorBase.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.CompilerServices;
 
 namespace Shadowsocks.Encryption
 {

shadowsocks-csharp/Encryption/EncryptorFactory.cs

@@ -11,8 +11,8 @@ namespace Shadowsocks.Encryption
     {
         public static string DefaultCipher = "chacha20-ietf-poly1305";
 
-        private static Dictionary<string, Type> _registeredEncryptors = new Dictionary<string, Type>();
-        private static Dictionary<string, CipherInfo> ciphers = new Dictionary<string, CipherInfo>();
+        private static readonly Dictionary<string, Type> _registeredEncryptors = new Dictionary<string, Type>();
+        private static readonly Dictionary<string, CipherInfo> ciphers = new Dictionary<string, CipherInfo>();
         private static readonly Type[] ConstructorTypes = { typeof(string), typeof(string) };
 
         static EncryptorFactory()
@@ -33,12 +33,12 @@ namespace Shadowsocks.Encryption
                     _registeredEncryptors.Add(method.Key, typeof(StreamRc4NativeEncryptor));
                 }
             }
-            foreach (var method in StreamAesBouncyCastleEncryptor.SupportedCiphers())
+            foreach (var method in StreamAesCfbBouncyCastleEncryptor.SupportedCiphers())
             {
                 if (!_registeredEncryptors.ContainsKey(method.Key))
                 {
                     ciphers.Add(method.Key, method.Value);
-                    _registeredEncryptors.Add(method.Key, typeof(StreamAesBouncyCastleEncryptor));
+                    _registeredEncryptors.Add(method.Key, typeof(StreamAesCfbBouncyCastleEncryptor));
                 }
             }
             foreach (var method in StreamChachaNaClEncryptor.SupportedCiphers())
@@ -77,7 +77,7 @@ namespace Shadowsocks.Encryption
             }
 
             method = method.ToLowerInvariant();
-            bool ok = _registeredEncryptors.TryGetValue(method, out Type t);
+            bool ok = _registeredEncryptors.TryGetValue(method, out Type? t);
             if (!ok)
             {
                 t = _registeredEncryptors[DefaultCipher];

shadowsocks-csharp/Encryption/Stream/ExtendedCfbBlockCipher.cs

@@ -13,9 +13,9 @@ namespace Org.BouncyCastle.Crypto.Modes
     public class ExtendedCfbBlockCipher
         : IBlockCipher
     {
-        private byte[] IV;
-        private byte[] cfbV;
-        private byte[] cfbOutV;
+        private readonly byte[] IV;
+        private readonly byte[] cfbV;
+        private readonly byte[] cfbOutV;
         private bool encrypting;
 
         private readonly int blockSize;
@@ -63,9 +63,8 @@ namespace Org.BouncyCastle.Crypto.Modes
             ICipherParameters parameters)
         {
             encrypting = forEncryption;
-            if (parameters is ParametersWithIV)
+            if (parameters is ParametersWithIV ivParam)
             {
-                ParametersWithIV ivParam = (ParametersWithIV)parameters;
                 byte[] iv = ivParam.GetIV();
                 int diff = IV.Length - iv.Length;
                 Array.Copy(iv, 0, IV, diff, iv.Length);

shadowsocks-csharp/Encryption/Stream/StreamAesBouncyCastleEncryptor.cs

@@ -3,23 +3,24 @@ using Org.BouncyCastle.Crypto.Modes;
 using Org.BouncyCastle.Crypto.Parameters;
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 
 namespace Shadowsocks.Encryption.Stream
 {
 
-    public class StreamAesBouncyCastleEncryptor : StreamEncryptor
+    public class StreamAesCfbBouncyCastleEncryptor : StreamEncryptor
     {
-        byte[] cfbBuf = new byte[MaxInputSize + 128];
+        readonly byte[] cfbBuf = new byte[MaxInputSize + 128];
         int ptr = 0;
         readonly ExtendedCfbBlockCipher b;
-        public StreamAesBouncyCastleEncryptor(string method, string password) : base(method, password)
+        public StreamAesCfbBouncyCastleEncryptor(string method, string password) : base(method, password)
         {
             b = new ExtendedCfbBlockCipher(new AesEngine(), 128);
         }
 
-        protected override void initCipher(byte[] iv, bool isEncrypt)
+        protected override void InitCipher(byte[] iv, bool isEncrypt)
         {
-            base.initCipher(iv, isEncrypt);
+            base.InitCipher(iv, isEncrypt);
             b.Init(isEncrypt, new ParametersWithIV(new KeyParameter(key), iv));
         }
 
@@ -35,6 +36,7 @@ namespace Shadowsocks.Encryption.Stream
             return cipher.Length;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveOptimization | MethodImplOptions.AggressiveInlining)]
         private void CipherUpdate(ReadOnlySpan<byte> i, Span<byte> o)
         {
             Span<byte> ob = new byte[o.Length + 128];
@@ -82,7 +84,7 @@ namespace Shadowsocks.Encryption.Stream
             return _ciphers;
         }
 
-        protected override Dictionary<string, CipherInfo> getCiphers()
+        protected override Dictionary<string, CipherInfo> GetCiphers()
         {
             return _ciphers;
         }

shadowsocks-csharp/Encryption/Stream/StreamChachaNaClEncryptor.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using NaCl.Core;
 
 namespace Shadowsocks.Encryption.Stream
@@ -7,15 +8,16 @@ namespace Shadowsocks.Encryption.Stream
     public class StreamChachaNaClEncryptor : StreamEncryptor
     {
         const int BlockSize = 64;
+
         // tcp is stream, which can split into chunks at unexpected position...
         // so we need some special handling, as we can't read all data before encrypt
-        
+
         // we did it in AEADEncryptor.cs for AEAD, it can operate at block level
         // but we need do it ourselves in stream cipher.
 
         // when new data arrive, put it on correct offset
         // and update it, ignore other data, get it in correct offset...
-        byte[] chachaBuf = new byte[MaxInputSize + BlockSize];
+        readonly byte[] chachaBuf = new byte[MaxInputSize + BlockSize];
         // the 'correct offset', always in 0~BlockSize range, so input data always fit into buffer
         int remain = 0;
         // increase counter manually...
@@ -34,6 +36,7 @@ namespace Shadowsocks.Encryption.Stream
             return CipherUpdate(plain, cipher, true);
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveOptimization | MethodImplOptions.AggressiveInlining)]
         private int CipherUpdate(ReadOnlySpan<byte> i, Span<byte> o, bool enc)
         {
             int len = i.Length;
@@ -58,7 +61,7 @@ namespace Shadowsocks.Encryption.Stream
             return _ciphers;
         }
 
-        protected override Dictionary<string, CipherInfo> getCiphers()
+        protected override Dictionary<string, CipherInfo> GetCiphers()
         {
             return _ciphers;
         }

shadowsocks-csharp/Encryption/Stream/StreamEncryptor.cs

@@ -1,6 +1,7 @@
 using NLog;
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using System.Text;
 
 namespace Shadowsocks.Encryption.Stream
@@ -26,7 +27,7 @@ namespace Shadowsocks.Encryption.Stream
         public StreamEncryptor(string method, string password)
             : base(method, password)
         {
-            CipherInfo = getCiphers()[method.ToLower()];
+            CipherInfo = GetCiphers()[method.ToLower()];
             cipherFamily = CipherInfo.Type;
             StreamCipherParameter parameter = (StreamCipherParameter)CipherInfo.CipherParameter;
             keyLen = parameter.KeySize;
@@ -37,7 +38,7 @@ namespace Shadowsocks.Encryption.Stream
             logger.Dump($"key {instanceId}", key, keyLen);
         }
 
-        protected abstract Dictionary<string, CipherInfo> getCiphers();
+        protected abstract Dictionary<string, CipherInfo> GetCiphers();
 
         private void InitKey(string password)
         {
@@ -51,6 +52,7 @@ namespace Shadowsocks.Encryption.Stream
             LegacyDeriveKey(passbuf, key, keyLen);
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void LegacyDeriveKey(byte[] password, byte[] key, int keylen)
         {
             byte[] result = new byte[password.Length + MD5Length];
@@ -73,7 +75,7 @@ namespace Shadowsocks.Encryption.Stream
             }
         }
 
-        protected virtual void initCipher(byte[] iv, bool isEncrypt)
+        protected virtual void InitCipher(byte[] iv, bool isEncrypt)
         {
             if (ivLen == 0)
             {
@@ -88,6 +90,7 @@ namespace Shadowsocks.Encryption.Stream
         protected abstract int CipherDecrypt(Span<byte> plain, ReadOnlySpan<byte> cipher);
 
         #region TCP
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int Encrypt(ReadOnlySpan<byte> plain, Span<byte> cipher)
         {
             int cipherOffset = 0;
@@ -96,7 +99,7 @@ namespace Shadowsocks.Encryption.Stream
             {
                 // Generate IV
                 byte[] ivBytes = RNG.GetBytes(ivLen);
-                initCipher(ivBytes, true);
+                InitCipher(ivBytes, true);
                 ivBytes.CopyTo(cipher);
                 cipherOffset = ivLen;
                 cipher = cipher.Slice(cipherOffset);
@@ -111,9 +114,9 @@ namespace Shadowsocks.Encryption.Stream
         }
 
         private int recieveCtr = 0;
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int Decrypt(Span<byte> plain, ReadOnlySpan<byte> cipher)
         {
-            Span<byte> tmp;// = cipher;
             logger.Trace($"{instanceId} decrypt TCP, read iv: {!ivReady}");
 
             int cipherOffset = 0;
@@ -135,14 +138,13 @@ namespace Shadowsocks.Encryption.Stream
                 {
                     // read iv
                     byte[] iv = sharedBuffer.AsSpan(0, ivLen).ToArray();
-                    initCipher(iv, false);
+                    InitCipher(iv, false);
                 }
                 else
                 {
-                    initCipher(Array.Empty<byte>(), false);
+                    InitCipher(Array.Empty<byte>(), false);
                 }
                 cipherOffset += ivLen;
-                tmp = sharedBuffer.AsSpan(ivLen, recieveCtr - ivLen);
             }
 
             // read all data from buffer
@@ -156,17 +158,19 @@ namespace Shadowsocks.Encryption.Stream
         #endregion
 
         #region UDP
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int EncryptUDP(ReadOnlySpan<byte> plain, Span<byte> cipher)
         {
             byte[] iv = RNG.GetBytes(ivLen);
             iv.CopyTo(cipher);
-            initCipher(iv, true);
+            InitCipher(iv, true);
             return ivLen + CipherEncrypt(plain, cipher.Slice(ivLen));
         }
 
+        [MethodImpl(MethodImplOptions.Synchronized | MethodImplOptions.AggressiveOptimization)]
         public override int DecryptUDP(Span<byte> plain, ReadOnlySpan<byte> cipher)
         {
-            initCipher(cipher.Slice(0, ivLen).ToArray(), false);
+            InitCipher(cipher.Slice(0, ivLen).ToArray(), false);
             return CipherDecrypt(plain, cipher.Slice(ivLen));
         }
 

shadowsocks-csharp/Encryption/Stream/StreamPlainNativeEncryptor.cs

@@ -33,7 +33,7 @@ namespace Shadowsocks.Encryption.Stream
             return _ciphers;
         }
 
-        protected override Dictionary<string, CipherInfo> getCiphers()
+        protected override Dictionary<string, CipherInfo> GetCiphers()
         {
             return _ciphers;
         }

shadowsocks-csharp/Encryption/Stream/StreamRc4NativeEncryptor.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 
 namespace Shadowsocks.Encryption.Stream
 {
@@ -11,9 +12,9 @@ namespace Shadowsocks.Encryption.Stream
         {
         }
 
-        protected override void initCipher(byte[] iv, bool isEncrypt)
+        protected override void InitCipher(byte[] iv, bool isEncrypt)
         {
-            base.initCipher(iv, isEncrypt);
+            base.InitCipher(iv, isEncrypt);
             // rc4-md5 is rc4 with md5 based session key
             if (cipherFamily == CipherFamily.Rc4Md5)
             {
@@ -39,6 +40,7 @@ namespace Shadowsocks.Encryption.Stream
             return CipherUpdate(cipher, plain);
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private int CipherUpdate(ReadOnlySpan<byte> i, Span<byte> o)
         {
             // don't know why we need third array, but it works...
@@ -62,7 +64,7 @@ namespace Shadowsocks.Encryption.Stream
             return _ciphers;
         }
 
-        protected override Dictionary<string, CipherInfo> getCiphers()
+        protected override Dictionary<string, CipherInfo> GetCiphers()
         {
             return _ciphers;
         }
@@ -75,7 +77,7 @@ namespace Shadowsocks.Encryption.Stream
             public int index2 = 0;
         }
 
-        private Context ctx = new Context();
+        private readonly Context ctx = new Context();
 
         private byte[] SBox(byte[] key)
         {
@@ -96,6 +98,7 @@ namespace Shadowsocks.Encryption.Stream
             return s;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         private void RC4(Context ctx, Span<byte> s, Span<byte> data, int length)
         {
             for (int n = 0; n < length; n++)
@@ -110,6 +113,7 @@ namespace Shadowsocks.Encryption.Stream
             }
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static void Swap(Span<byte> s, int i, int j)
         {
             byte c = s[i];

test/CryptographyTest.cs

@@ -11,7 +11,7 @@ namespace Shadowsocks.Test
     [TestClass]
     public class CryptographyTest
     {
-        Random random = new Random();
+        readonly Random random = new Random();
 
 
         [TestMethod]
@@ -161,9 +161,9 @@ namespace Shadowsocks.Test
         [TestMethod]
         public void TestStreamAesCfbBouncyCastleEncryption()
         {
-            TestEncryptionMethod(typeof(StreamAesBouncyCastleEncryptor), "aes-128-cfb");
-            TestEncryptionMethod(typeof(StreamAesBouncyCastleEncryptor), "aes-192-cfb");
-            TestEncryptionMethod(typeof(StreamAesBouncyCastleEncryptor), "aes-256-cfb");
+            TestEncryptionMethod(typeof(StreamAesCfbBouncyCastleEncryptor), "aes-128-cfb");
+            TestEncryptionMethod(typeof(StreamAesCfbBouncyCastleEncryptor), "aes-192-cfb");
+            TestEncryptionMethod(typeof(StreamAesCfbBouncyCastleEncryptor), "aes-256-cfb");
         }
         [TestMethod]
         public void TestStreamChachaNaClEncryption()