buggy chacha20-ietf

shadowsocks-csharp/Encryption/EncryptorFactory.cs

@@ -41,6 +41,14 @@ namespace Shadowsocks.Encryption
                     _registeredEncryptors.Add(method.Key, typeof(StreamAesBouncyCastleEncryptor));
                 }
             }
+            foreach (var method in StreamChachaNaClEncryptor.SupportedCiphers())
+            {
+                if (!_registeredEncryptors.ContainsKey(method.Key))
+                {
+                    ciphers.Add(method.Key, method.Value);
+                    _registeredEncryptors.Add(method.Key, typeof(StreamChachaNaClEncryptor));
+                }
+            }
 
 
             foreach (var method in AEADAesGcmNativeEncryptor.SupportedCiphers())

shadowsocks-csharp/Encryption/Stream/StreamChachaNaClEncryptor.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using NaCl.Core;
+
+namespace Shadowsocks.Encryption.Stream
+{
+    public class StreamChachaNaClEncryptor : StreamEncryptor
+    {
+        ChaCha20 c;
+        public StreamChachaNaClEncryptor(string method, string password) : base(method, password)
+        {
+            c = new ChaCha20(key, 0);
+        }
+
+        protected override int CipherDecrypt(Span<byte> plain, Span<byte> cipher)
+        {
+            var p = c.Decrypt(cipher, iv);
+            p.CopyTo(plain);
+            return p.Length;
+        }
+
+        protected override int CipherEncrypt(Span<byte> plain, Span<byte> cipher)
+        {
+            var e = c.Encrypt(plain, iv);
+            e.CopyTo(cipher);
+            return e.Length;
+        }
+
+        protected override void cipherUpdate(bool isEncrypt, int length, byte[] buf, byte[] outbuf)
+        {
+            var i = buf.AsSpan().Slice(0, length);
+            if (isEncrypt)
+            {
+                CipherEncrypt(i, outbuf);
+            }
+            else
+            {
+                CipherDecrypt(outbuf, i);
+            }
+        }
+
+        #region Ciphers
+        private static readonly Dictionary<string, CipherInfo> _ciphers = new Dictionary<string, CipherInfo>
+        {
+            { "chacha20-ietf", new CipherInfo("chacha20-ietf", 32, 12, CipherFamily.Chacha20) },
+        };
+        public static Dictionary<string, CipherInfo> SupportedCiphers()
+        {
+            return _ciphers;
+        }
+
+        protected override Dictionary<string, CipherInfo> getCiphers()
+        {
+            return _ciphers;
+        }
+        #endregion
+    }
+}

test/CryptographyTest.cs

@@ -165,5 +165,10 @@ namespace Shadowsocks.Test
         {
             TestEncryptionMethod(typeof(StreamAesBouncyCastleEncryptor), "aes-256-cfb");
         }
+        [TestMethod]
+        public void TestStreamChachaNaClEncryption()
+        {
+            TestEncryptionMethod(typeof(StreamChachaNaClEncryptor), "chacha20-ietf");
+        }
     }
 }