Refine Encryption module (#717)

- use EncryptorInfo struct instead of Dictionary<string, int[]>>

shadowsocks-csharp/Encryption/EncryptorBase.cs

@@ -2,6 +2,22 @@
 
 namespace Shadowsocks.Encryption
 {
+    public struct EncryptorInfo
+    {
+        public string name;
+        public int key_size;
+        public int iv_size;
+        public int type;
+
+        public EncryptorInfo(string name, int key_size, int iv_size, int type)
+        {
+            this.name = name;
+            this.key_size = key_size;
+            this.iv_size = iv_size;
+            this.type = type;
+        }
+    }
+
     public abstract class EncryptorBase
         : IEncryptor
     {

shadowsocks-csharp/Encryption/IVEncryptor.cs

@@ -16,8 +16,7 @@ namespace Shadowsocks.Encryption
 
         protected static byte[] tempbuf = new byte[MAX_INPUT_SIZE];
 
-        protected Dictionary<string, Dictionary<string, int[]>> ciphers;
-        protected Dictionary<string, int[]> ciphersDetail;
+        protected Dictionary<string, EncryptorInfo> ciphers;
 
         private static readonly ConcurrentDictionary<string, byte[]> CachedKeys = new ConcurrentDictionary<string, byte[]>();
         protected byte[] _encryptIV;
@@ -28,7 +27,7 @@ namespace Shadowsocks.Encryption
         protected int _cipher;
         // cipher name in MbedTLS, useless when using LibSodium
         protected string _cipherMbedName;
-        protected int[] _cipherInfo;
+        protected EncryptorInfo _cipherInfo;
         protected byte[] _key;
         protected int keyLen;
         protected int ivLen;
@@ -39,7 +38,7 @@ namespace Shadowsocks.Encryption
             InitKey(method, password);
         }
 
-        protected abstract Dictionary<string, Dictionary<string, int[]>> getCiphers();
+        protected abstract Dictionary<string, EncryptorInfo> getCiphers();
 
         private void InitKey(string method, string password)
         {
@@ -47,16 +46,15 @@ namespace Shadowsocks.Encryption
             _method = method;
             string k = method + ":" + password;
             ciphers = getCiphers();
-            ciphersDetail = ciphers[_method];
-            _cipherMbedName = ciphersDetail.Keys.FirstOrDefault();
-            _cipherInfo = ciphers[_method][_cipherMbedName];
-            _cipher = _cipherInfo[2];
+            _cipherInfo = ciphers[_method];
+            _cipherMbedName = _cipherInfo.name;
+            _cipher = _cipherInfo.type;
             if (_cipher == 0)
             {
                 throw new Exception("method not found");
             }
-            keyLen = _cipherInfo[0];
-            ivLen = _cipherInfo[1];
+            keyLen = _cipherInfo.key_size;
+            ivLen = _cipherInfo.iv_size;
             _key = CachedKeys.GetOrAdd(k, (nk) =>
             {
                 byte[] passbuf = Encoding.UTF8.GetBytes(password);

shadowsocks-csharp/Encryption/MbedTLSEncryptor.cs

@@ -20,18 +20,18 @@ namespace Shadowsocks.Encryption
         {
         }
 
-        private static Dictionary<string, Dictionary<string, int[]>> _ciphers = new Dictionary<string, Dictionary<string, int[]>> {
-            { "aes-128-cfb", new Dictionary<string, int[]> { { "AES-128-CFB128", new int[] { 16, 16, CIPHER_AES } } } },
-            { "aes-192-cfb", new Dictionary<string, int[]> { { "AES-192-CFB128", new int[] { 24, 16, CIPHER_AES } } } },
-            { "aes-256-cfb", new Dictionary<string, int[]> { { "AES-256-CFB128", new int[] { 32, 16, CIPHER_AES } } } },
-            { "aes-128-ctr", new Dictionary<string, int[]> { { "AES-128-CTR", new int[] { 16, 16, CIPHER_AES } } } },
-            { "aes-192-ctr", new Dictionary<string, int[]> { { "AES-192-CTR", new int[] { 24, 16, CIPHER_AES } } } },
-            { "aes-256-ctr", new Dictionary<string, int[]> { { "AES-256-CTR", new int[] { 32, 16, CIPHER_AES } } } },
-            { "bf-cfb", new Dictionary<string, int[]> { { "BLOWFISH-CFB64", new int[] { 16, 8, CIPHER_BLOWFISH } } } },
-            { "camellia-128-cfb", new Dictionary<string, int[]> { { "CAMELLIA-128-CFB128", new int[] { 16, 16, CIPHER_CAMELLIA } } } },
-            { "camellia-192-cfb", new Dictionary<string, int[]> { { "CAMELLIA-192-CFB128", new int[] { 24, 16, CIPHER_CAMELLIA } } } },
-            { "camellia-256-cfb", new Dictionary<string, int[]> { { "CAMELLIA-256-CFB128", new int[] { 32, 16, CIPHER_CAMELLIA } } } },
-            { "rc4-md5", new Dictionary<string, int[]> { { "ARC4-128", new int[] { 16, 16, CIPHER_RC4 } } } }
+        private static Dictionary<string, EncryptorInfo> _ciphers = new Dictionary<string, EncryptorInfo> {
+            { "aes-128-cfb", new EncryptorInfo("AES-128-CFB128", 16, 16, CIPHER_AES) },
+            { "aes-192-cfb", new EncryptorInfo("AES-192-CFB128", 24, 16, CIPHER_AES) },
+            { "aes-256-cfb", new EncryptorInfo("AES-256-CFB128", 32, 16, CIPHER_AES) },
+            { "aes-128-ctr", new EncryptorInfo("AES-128-CTR", 16, 16, CIPHER_AES) },
+            { "aes-192-ctr", new EncryptorInfo("AES-192-CTR", 24, 16, CIPHER_AES) },
+            { "aes-256-ctr", new EncryptorInfo("AES-256-CTR", 32, 16, CIPHER_AES) },
+            { "bf-cfb", new EncryptorInfo("BLOWFISH-CFB64", 16, 8, CIPHER_BLOWFISH) },
+            { "camellia-128-cfb", new EncryptorInfo("CAMELLIA-128-CFB128", 16, 16, CIPHER_CAMELLIA) },
+            { "camellia-192-cfb", new EncryptorInfo("CAMELLIA-192-CFB128", 24, 16, CIPHER_CAMELLIA) },
+            { "camellia-256-cfb", new EncryptorInfo("CAMELLIA-256-CFB128", 32, 16, CIPHER_CAMELLIA) },
+            { "rc4-md5", new EncryptorInfo("ARC4-128", 16, 16, CIPHER_RC4) }
         };
 
         public static List<string> SupportedCiphers()
@@ -39,7 +39,7 @@ namespace Shadowsocks.Encryption
             return new List<string>(_ciphers.Keys);
         }
 
-        protected override Dictionary<string, Dictionary<string, int[]>> getCiphers()
+        protected override Dictionary<string, EncryptorInfo> getCiphers()
         {
             return _ciphers;
         }

shadowsocks-csharp/Encryption/SodiumEncryptor.cs

@@ -24,13 +24,13 @@ namespace Shadowsocks.Encryption
         {
         }
 
-        private static Dictionary<string, Dictionary<string, int[]>> _ciphers = new Dictionary<string, Dictionary<string, int[]>> {
-            { "salsa20", new Dictionary<string, int[]> { { "salsa20", new int[] { 32, 8, CIPHER_SALSA20 } } } },
-            { "chacha20", new Dictionary<string, int[]> { { "chacha20", new int[] { 32, 8, CIPHER_CHACHA20 } } } },
-            { "chacha20-ietf", new Dictionary<string, int[]> { { "chacha20-ietf", new int[] { 32, 12, CIPHER_CHACHA20_IETF } } } }
+        private static Dictionary<string, EncryptorInfo> _ciphers = new Dictionary<string, EncryptorInfo> {
+            { "salsa20", new EncryptorInfo("salsa20", 32, 8, CIPHER_SALSA20) },
+            { "chacha20", new EncryptorInfo("chacha20", 32, 8, CIPHER_CHACHA20) },
+            { "chacha20-ietf", new EncryptorInfo("chacha20-ietf", 32, 12, CIPHER_CHACHA20_IETF) }
         };
 
-        protected override Dictionary<string, Dictionary<string, int[]>> getCiphers()
+        protected override Dictionary<string, EncryptorInfo> getCiphers()
         {
             return _ciphers;
         }