diff --git a/shadowsocks-csharp/Controller/Service/TCPRelay.cs b/shadowsocks-csharp/Controller/Service/TCPRelay.cs
index bf0497d4..c1b39a04 100644
--- a/shadowsocks-csharp/Controller/Service/TCPRelay.cs
+++ b/shadowsocks-csharp/Controller/Service/TCPRelay.cs
@@ -124,7 +124,7 @@ namespace Shadowsocks.Controller
             {
                 throw new ArgumentException("No server configured");
             }
-            this.encryptor = EncryptorFactory.GetEncryptor(server.method, server.password);
+            this.encryptor = EncryptorFactory.GetEncryptor(server.method, server.password, server.one_time_auth);
             this.server = server;
         }
 
diff --git a/shadowsocks-csharp/Data/cn.txt b/shadowsocks-csharp/Data/cn.txt
index 81022f99..813578b7 100644
--- a/shadowsocks-csharp/Data/cn.txt
+++ b/shadowsocks-csharp/Data/cn.txt
@@ -39,6 +39,7 @@ Password=密码
 Encryption=加密
 Proxy Port=代理端口
 Remarks=备注
+One-time authorization=一次性授权
 OK=确定
 Cancel=取消
 New server=未配置的服务器
diff --git a/shadowsocks-csharp/Data/libsscrypto2.dll.gz b/shadowsocks-csharp/Data/libsscrypto2.dll.gz
new file mode 100644
index 00000000..83f7aab1
Binary files /dev/null and b/shadowsocks-csharp/Data/libsscrypto2.dll.gz differ
diff --git a/shadowsocks-csharp/Encryption/EncryptorBase.cs b/shadowsocks-csharp/Encryption/EncryptorBase.cs
index 8b5cd61a..b92233ec 100644
--- a/shadowsocks-csharp/Encryption/EncryptorBase.cs
+++ b/shadowsocks-csharp/Encryption/EncryptorBase.cs
@@ -8,14 +8,16 @@ namespace Shadowsocks.Encryption
     {
         public const int MAX_INPUT_SIZE = 32768;
 
-        protected EncryptorBase(string method, string password)
+        protected EncryptorBase(string method, string password, bool onetimeauth)
         {
             Method = method;
             Password = password;
+            OnetimeAuth = onetimeauth;
         }
 
         protected string Method;
         protected string Password;
+        protected bool OnetimeAuth;
 
         protected byte[] GetPasswordHash()
         {
diff --git a/shadowsocks-csharp/Encryption/EncryptorFactory.cs b/shadowsocks-csharp/Encryption/EncryptorFactory.cs
index d5ff15e3..120bd53c 100644
--- a/shadowsocks-csharp/Encryption/EncryptorFactory.cs
+++ b/shadowsocks-csharp/Encryption/EncryptorFactory.cs
@@ -8,7 +8,7 @@ namespace Shadowsocks.Encryption
     {
         private static Dictionary<string, Type> _registeredEncryptors;
 
-        private static Type[] _constructorTypes = new Type[] { typeof(string), typeof(string) };
+        private static Type[] _constructorTypes = new Type[] { typeof(string), typeof(string), typeof(bool) };
 
         static EncryptorFactory()
         {
@@ -27,7 +27,7 @@ namespace Shadowsocks.Encryption
             }
         }
 
-        public static IEncryptor GetEncryptor(string method, string password)
+        public static IEncryptor GetEncryptor(string method, string password, bool onetimeauth = false)
         {
             if (string.IsNullOrEmpty(method))
             {
@@ -36,7 +36,7 @@ namespace Shadowsocks.Encryption
             method = method.ToLowerInvariant();
             Type t = _registeredEncryptors[method];
             ConstructorInfo c = t.GetConstructor(_constructorTypes);
-            IEncryptor result = (IEncryptor)c.Invoke(new object[] { method, password });
+            IEncryptor result = (IEncryptor)c.Invoke(new object[] { method, password, onetimeauth });
             return result;
         }
     }
diff --git a/shadowsocks-csharp/Encryption/IVEncryptor.cs b/shadowsocks-csharp/Encryption/IVEncryptor.cs
index b82d3adf..869cdb58 100755
--- a/shadowsocks-csharp/Encryption/IVEncryptor.cs
+++ b/shadowsocks-csharp/Encryption/IVEncryptor.cs
@@ -2,12 +2,19 @@
 using System.Collections.Generic;
 using System.Security.Cryptography;
 using System.Text;
+using System.Net;
 
 namespace Shadowsocks.Encryption
 {
     public abstract class IVEncryptor
         : EncryptorBase
     {
+        public const int ONETIMEAUTH_FLAG = 0x10;
+        public const int ADDRTYPE_MASK = 0xF;
+        public const int ONETIMEAUTH_BYTES = 16;
+        public const int CRC_BUF_LEN = 128;
+        public const int CRC_BYTES = 2;
+
         protected static byte[] tempbuf = new byte[MAX_INPUT_SIZE];
 
         protected Dictionary<string, int[]> ciphers;
@@ -25,11 +32,17 @@ namespace Shadowsocks.Encryption
         protected byte[] _key;
         protected int keyLen;
         protected int ivLen;
+        protected byte[] crc_buf;
+        protected int crc_idx = 0;
 
-        public IVEncryptor(string method, string password)
-            : base(method, password)
+        public IVEncryptor(string method, string password, bool onetimeauth)
+            : base(method, password, onetimeauth)
         {
             InitKey(method, password);
+            if (OnetimeAuth)
+            {
+                crc_buf = new byte[CRC_BUF_LEN];
+            }
         }
 
         protected abstract Dictionary<string, int[]> getCiphers();
@@ -112,6 +125,28 @@ namespace Shadowsocks.Encryption
 
         protected abstract void cipherUpdate(bool isCipher, int length, byte[] buf, byte[] outbuf);
 
+        protected int GetSSHeadLength(byte[] buf, int length)
+        {
+            int len = 0;
+            int atyp = length > 0 ? (buf[0] & ADDRTYPE_MASK) : 0;
+            if (atyp == 1)
+            {
+                len = 7; // atyp (1 bytes) + ipv4 (4 bytes) + port (2 bytes)
+            }
+            else if (atyp == 3 && length > 1)
+            {
+                int nameLen = buf[1];
+                len = 4 + nameLen; // atyp (1 bytes) + name length (1 bytes) + name (n bytes) + port (2 bytes)
+            }
+            else if (atyp == 4)
+            {
+                len = 19; // atyp (1 bytes) + ipv6 (16 bytes) + port (2 bytes)
+            }
+            if (len == 0 || len > length)
+                throw new Exception($"invalid header with addr type {atyp}");
+            return len;
+        }
+
         public override void Encrypt(byte[] buf, int length, byte[] outbuf, out int outlength)
         {
             if (!_encryptIVSent)
@@ -122,6 +157,24 @@ namespace Shadowsocks.Encryption
                 outlength = length + ivLen;
                 lock (tempbuf)
                 {
+                    if (OnetimeAuth)
+                    {
+                        lock(crc_buf)
+                        {
+                            int headLen = GetSSHeadLength(buf, length);
+                            int data_len = length - headLen;
+                            Buffer.BlockCopy(buf, headLen, buf, headLen + ONETIMEAUTH_BYTES, data_len);
+                            buf[0] |= ONETIMEAUTH_FLAG;
+                            byte[] auth = new byte[ONETIMEAUTH_BYTES];
+                            Sodium.ss_onetimeauth(auth, buf, headLen, _encryptIV, ivLen, _key, keyLen);
+                            Buffer.BlockCopy(auth, 0, buf, headLen, ONETIMEAUTH_BYTES);
+                            int buf_offset = headLen + ONETIMEAUTH_BYTES;
+                            int rc = Sodium.ss_gen_crc(buf, ref buf_offset, ref data_len, crc_buf, ref crc_idx, buf.Length);
+                            if (rc != 0)
+                                throw new Exception("failed to generate crc");
+                            length = headLen + ONETIMEAUTH_BYTES + data_len;
+                        }
+                    }
                     cipherUpdate(true, length, buf, tempbuf);
                     outlength = length + ivLen;
                     Buffer.BlockCopy(tempbuf, 0, outbuf, ivLen, length);
@@ -129,6 +182,16 @@ namespace Shadowsocks.Encryption
             }
             else
             {
+                if (OnetimeAuth)
+                {
+                    lock(crc_buf)
+                    {
+                        int buf_offset = 0;
+                        int rc = Sodium.ss_gen_crc(buf, ref buf_offset, ref length, crc_buf, ref crc_idx, buf.Length);
+                        if (rc != 0)
+                            throw new Exception("failed to generate crc");
+                    }
+                }
                 outlength = length;
                 cipherUpdate(true, length, buf, outbuf);
             }
@@ -154,5 +217,6 @@ namespace Shadowsocks.Encryption
                 cipherUpdate(false, length, buf, outbuf);
             }
         }
+
     }
 }
diff --git a/shadowsocks-csharp/Encryption/PolarSSLEncryptor.cs b/shadowsocks-csharp/Encryption/PolarSSLEncryptor.cs
index 6216c24d..3aca3f72 100755
--- a/shadowsocks-csharp/Encryption/PolarSSLEncryptor.cs
+++ b/shadowsocks-csharp/Encryption/PolarSSLEncryptor.cs
@@ -16,8 +16,8 @@ namespace Shadowsocks.Encryption
         private IntPtr _encryptCtx = IntPtr.Zero;
         private IntPtr _decryptCtx = IntPtr.Zero;
 
-        public PolarSSLEncryptor(string method, string password)
-            : base(method, password)
+        public PolarSSLEncryptor(string method, string password, bool onetimeauth)
+            : base(method, password, onetimeauth)
         {
             InitKey(method, password);
         }
diff --git a/shadowsocks-csharp/Encryption/Sodium.cs b/shadowsocks-csharp/Encryption/Sodium.cs
index 564aaeda..14403267 100755
--- a/shadowsocks-csharp/Encryption/Sodium.cs
+++ b/shadowsocks-csharp/Encryption/Sodium.cs
@@ -12,8 +12,15 @@ namespace Shadowsocks.Encryption
     public class Sodium
     {
         const string DLLNAME = "libsscrypto";
+        const string DLLNAME2 = "libsscrypto2";
 
         static Sodium()
+        {
+            LoadSSCryptoLibrary();
+            LoadSSCrypto2Library();
+        }
+
+        static void LoadSSCryptoLibrary()
         {
             string tempPath = Utils.GetTempPath();
             string dllPath = tempPath + "/libsscrypto.dll";
@@ -29,7 +36,24 @@ namespace Shadowsocks.Encryption
             {
                 Console.WriteLine(e.ToString());
             }
-            LoadLibrary(dllPath);
+        }
+
+        static void LoadSSCrypto2Library()
+        {
+            string tempPath = Utils.GetTempPath();
+            string dllPath = tempPath + "/libsscrypto2.dll";
+            try
+            {
+                FileManager.UncompressFile(dllPath, Resources.libsscrypto2_dll);
+                LoadLibrary(dllPath);
+            }
+            catch (IOException)
+            {
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine(e.ToString());
+            }
         }
 
         [DllImport("Kernel32.dll")]
@@ -40,5 +64,16 @@ namespace Shadowsocks.Encryption
 
         [DllImport(DLLNAME, CallingConvention = CallingConvention.Cdecl)]
         public extern static void crypto_stream_chacha20_xor_ic(byte[] c, byte[] m, ulong mlen, byte[] n, ulong ic, byte[] k);
+
+        [DllImport(DLLNAME2, CallingConvention = CallingConvention.Cdecl)]
+        public extern static int ss_gen_crc(byte[] buf, ref int buf_offset, ref int data_len,
+            byte[] crc_buf, ref int crc_idx, int buf_size);
+
+        [DllImport(DLLNAME2, CallingConvention = CallingConvention.Cdecl)]
+        public extern static int ss_onetimeauth(byte[] auth, 
+            byte[] msg, int msg_len, 
+            byte[] iv, int iv_len,
+            byte[] key, int key_len);
     }
 }
+
diff --git a/shadowsocks-csharp/Encryption/SodiumEncryptor.cs b/shadowsocks-csharp/Encryption/SodiumEncryptor.cs
index af51d0ac..8ab8e255 100755
--- a/shadowsocks-csharp/Encryption/SodiumEncryptor.cs
+++ b/shadowsocks-csharp/Encryption/SodiumEncryptor.cs
@@ -20,8 +20,8 @@ namespace Shadowsocks.Encryption
         protected ulong _encryptIC;
         protected ulong _decryptIC;
 
-        public SodiumEncryptor(string method, string password)
-            : base(method, password)
+        public SodiumEncryptor(string method, string password, bool onetimeauth)
+            : base(method, password, onetimeauth)
         {
             InitKey(method, password);
         }
diff --git a/shadowsocks-csharp/Encryption/TableEncryptor.cs b/shadowsocks-csharp/Encryption/TableEncryptor.cs
index db0a7db0..3de625a6 100644
--- a/shadowsocks-csharp/Encryption/TableEncryptor.cs
+++ b/shadowsocks-csharp/Encryption/TableEncryptor.cs
@@ -6,8 +6,8 @@ namespace Shadowsocks.Encryption
     public class TableEncryptor
         : EncryptorBase
     {
-        public TableEncryptor(string method, string password)
-            : base(method, password)
+        public TableEncryptor(string method, string password, bool onetimeauth)
+            : base(method, password, onetimeauth)
         {
             byte[] hash = GetPasswordHash();
             // TODO endian
diff --git a/shadowsocks-csharp/Model/Server.cs b/shadowsocks-csharp/Model/Server.cs
index 24dd1162..55134335 100755
--- a/shadowsocks-csharp/Model/Server.cs
+++ b/shadowsocks-csharp/Model/Server.cs
@@ -17,6 +17,7 @@ namespace Shadowsocks.Model
         public string password;
         public string method;
         public string remarks;
+        public bool one_time_auth;
 
         public override int GetHashCode()
         {
@@ -52,6 +53,7 @@ namespace Shadowsocks.Model
             this.method = "aes-256-cfb";
             this.password = "";
             this.remarks = "";
+            this.one_time_auth = false;
         }
 
         public Server(string ssURL) : this()
@@ -88,6 +90,9 @@ namespace Shadowsocks.Model
                 string[] parts = beforeAt.Split(new[] { ':' });
                 this.method = parts[0];
                 this.password = parts[1];
+
+                //TODO: read one_time_auth
+
             }
             catch (IndexOutOfRangeException)
             {
diff --git a/shadowsocks-csharp/Properties/Resources.Designer.cs b/shadowsocks-csharp/Properties/Resources.Designer.cs
index 198e9f48..a5891002 100644
--- a/shadowsocks-csharp/Properties/Resources.Designer.cs
+++ b/shadowsocks-csharp/Properties/Resources.Designer.cs
@@ -1,10 +1,10 @@
 //------------------------------------------------------------------------------
 // <auto-generated>
-//     This code was generated by a tool.
-//     Runtime Version:4.0.30319.42000
+//     此代码由工具生成。
+//     运行时版本:4.0.30319.42000
 //
-//     Changes to this file may cause incorrect behavior and will be lost if
-//     the code is regenerated.
+//     对此文件的更改可能会导致不正确的行为，并且如果
+//     重新生成代码，这些更改将会丢失。
 // </auto-generated>
 //------------------------------------------------------------------------------
 
@@ -13,12 +13,12 @@ namespace Shadowsocks.Properties {
     
     
     /// <summary>
-    ///   A strongly-typed resource class, for looking up localized strings, etc.
+    ///   一个强类型的资源类，用于查找本地化的字符串等。
     /// </summary>
-    // This class was auto-generated by the StronglyTypedResourceBuilder
-    // class via a tool like ResGen or Visual Studio.
-    // To add or remove a member, edit your .ResX file then rerun ResGen
-    // with the /str option, or rebuild your VS project.
+    // 此类是由 StronglyTypedResourceBuilder
+    // 类通过类似于 ResGen 或 Visual Studio 的工具自动生成的。
+    // 若要添加或移除成员，请编辑 .ResX 文件，然后重新运行 ResGen
+    // (以 /str 作为命令选项)，或重新生成 VS 项目。
     [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")]
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
@@ -33,7 +33,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Returns the cached ResourceManager instance used by this class.
+        ///   返回此类使用的缓存的 ResourceManager 实例。
         /// </summary>
         [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
         internal static global::System.Resources.ResourceManager ResourceManager {
@@ -47,8 +47,8 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Overrides the current thread's CurrentUICulture property for all
-        ///   resource lookups using this strongly typed resource class.
+        ///   使用此强类型资源类，为所有资源查找
+        ///   重写当前线程的 CurrentUICulture 属性。
         /// </summary>
         [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
         internal static global::System.Globalization.CultureInfo Culture {
@@ -61,7 +61,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Byte[].
+        ///   查找 System.Byte[] 类型的本地化资源。
         /// </summary>
         internal static byte[] abp_js {
             get {
@@ -71,30 +71,28 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to # translation for Simplified Chinese
-        ///
-        ///Shadowsocks=Shadowsocks
-        ///
-        ///# Menu items
-        ///
-        ///Enable System Proxy=启用系统代理
-        ///Mode=系统代理模式
-        ///PAC=PAC 模式
-        ///Global=全局模式
-        ///Servers=服务器
-        ///Edit Servers...=编辑服务器...
-        ///Start on Boot=开机启动
-        ///Allow Clients from LAN=允许来自局域网的连接
-        ///Local PAC=使用本地 PAC
-        ///Online PAC=使用在线 PAC
-        ///Edit Local PAC File...=编辑本地 PAC 文件...
-        ///Update Local PAC from GFWList=从 GFWList 更新本地 PAC
-        ///Edit User Rule for GFWList...=编辑 GFWList 的用户规则...
-        ///Show QRCode...=显示二维码...
-        ///Scan QRCode from Screen...=扫描屏幕上的二维码...
-        ///Show Logs...=显示日志...
-        ///About...=关于...
-        ///Quit=退出 [rest of string was truncated]&quot;;.
+        ///   查找类似 # translation for Simplified Chinese
+        ///
+        ///Shadowsocks=Shadowsocks
+        ///
+        ///# Menu items
+        ///
+        ///Enable System Proxy=启用系统代理
+        ///Mode=系统代理模式
+        ///PAC=PAC 模式
+        ///Global=全局模式
+        ///Servers=服务器
+        ///Edit Servers...=编辑服务器...
+        ///Start on Boot=开机启动
+        ///Allow Clients from LAN=允许来自局域网的连接
+        ///Local PAC=使用本地 PAC
+        ///Online PAC=使用在线 PAC
+        ///Edit Local PAC File...=编辑本地 PAC 文件...
+        ///Update Local PAC from GFWList=从 GFWList 更新本地 PAC
+        ///Edit User Rule for GFWList...=编辑 GFWList 的用户规则...
+        ///Show QRCode...=显示二维码...
+        ///Scan QRCode from Screen...=扫描屏幕上的二维码...
+        ///Availability Statistic [字符串的其余部分被截断]&quot;; 的本地化字符串。
         /// </summary>
         internal static string cn {
             get {
@@ -103,7 +101,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Byte[].
+        ///   查找 System.Byte[] 类型的本地化资源。
         /// </summary>
         internal static byte[] libsscrypto_dll {
             get {
@@ -113,7 +111,17 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Byte[].
+        ///   查找 System.Byte[] 类型的本地化资源。
+        /// </summary>
+        internal static byte[] libsscrypto2_dll {
+            get {
+                object obj = ResourceManager.GetObject("libsscrypto2_dll", resourceCulture);
+                return ((byte[])(obj));
+            }
+        }
+        
+        /// <summary>
+        ///   查找 System.Byte[] 类型的本地化资源。
         /// </summary>
         internal static byte[] mgwz_dll {
             get {
@@ -123,11 +131,11 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to listen-address __POLIPO_BIND_IP__:8123
+        ///   查找类似 listen-address __POLIPO_BIND_IP__:8123
         ///show-on-task-bar 0
         ///activity-animation 0
         ///forward-socks5 / 127.0.0.1:__SOCKS_PORT__ .
-        ///hide-console.
+        ///hide-console 的本地化字符串。
         /// </summary>
         internal static string privoxy_conf {
             get {
@@ -136,7 +144,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Byte[].
+        ///   查找 System.Byte[] 类型的本地化资源。
         /// </summary>
         internal static byte[] privoxy_exe {
             get {
@@ -146,7 +154,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Byte[].
+        ///   查找 System.Byte[] 类型的本地化资源。
         /// </summary>
         internal static byte[] proxy_pac_txt {
             get {
@@ -156,7 +164,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Drawing.Bitmap.
+        ///   查找 System.Drawing.Bitmap 类型的本地化资源。
         /// </summary>
         internal static System.Drawing.Bitmap ss16 {
             get {
@@ -166,7 +174,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Drawing.Bitmap.
+        ///   查找 System.Drawing.Bitmap 类型的本地化资源。
         /// </summary>
         internal static System.Drawing.Bitmap ss20 {
             get {
@@ -176,7 +184,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Drawing.Bitmap.
+        ///   查找 System.Drawing.Bitmap 类型的本地化资源。
         /// </summary>
         internal static System.Drawing.Bitmap ss24 {
             get {
@@ -186,7 +194,7 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized resource of type System.Drawing.Bitmap.
+        ///   查找 System.Drawing.Bitmap 类型的本地化资源。
         /// </summary>
         internal static System.Drawing.Bitmap ssw128 {
             get {
@@ -196,9 +204,9 @@ namespace Shadowsocks.Properties {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to ! Put user rules line by line in this file.
+        ///   查找类似 ! Put user rules line by line in this file.
         ///! See https://adblockplus.org/en/filter-cheatsheet
-        ///.
+        /// 的本地化字符串。
         /// </summary>
         internal static string user_rule {
             get {
diff --git a/shadowsocks-csharp/Properties/Resources.resx b/shadowsocks-csharp/Properties/Resources.resx
index aa0c2f63..36dc1386 100755
--- a/shadowsocks-csharp/Properties/Resources.resx
+++ b/shadowsocks-csharp/Properties/Resources.resx
@@ -124,6 +124,9 @@
   <data name="cn" type="System.Resources.ResXFileRef, System.Windows.Forms">
     <value>..\data\cn.txt;System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089;utf-8</value>
   </data>
+  <data name="libsscrypto2_dll" type="System.Resources.ResXFileRef, System.Windows.Forms">
+    <value>..\Data\libsscrypto2.dll.gz;System.Byte[], mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </data>
   <data name="libsscrypto_dll" type="System.Resources.ResXFileRef, System.Windows.Forms">
     <value>..\data\libsscrypto.dll.gz;System.Byte[], mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </data>
diff --git a/shadowsocks-csharp/View/ConfigForm.Designer.cs b/shadowsocks-csharp/View/ConfigForm.Designer.cs
index f8b5940a..e985937e 100755
--- a/shadowsocks-csharp/View/ConfigForm.Designer.cs
+++ b/shadowsocks-csharp/View/ConfigForm.Designer.cs
@@ -55,6 +55,7 @@
             this.ProxyPortLabel = new System.Windows.Forms.Label();
             this.tableLayoutPanel3 = new System.Windows.Forms.TableLayoutPanel();
             this.tableLayoutPanel4 = new System.Windows.Forms.TableLayoutPanel();
+            this.OneTimeAuth = new System.Windows.Forms.CheckBox();
             this.tableLayoutPanel1.SuspendLayout();
             this.ServerGroupBox.SuspendLayout();
             this.tableLayoutPanel2.SuspendLayout();
@@ -81,18 +82,20 @@
             this.tableLayoutPanel1.Controls.Add(this.PasswordTextBox, 1, 2);
             this.tableLayoutPanel1.Controls.Add(this.EncryptionLabel, 0, 3);
             this.tableLayoutPanel1.Controls.Add(this.EncryptionSelect, 1, 3);
+            this.tableLayoutPanel1.Controls.Add(this.OneTimeAuth, 1, 6);
             this.tableLayoutPanel1.Location = new System.Drawing.Point(8, 21);
             this.tableLayoutPanel1.Margin = new System.Windows.Forms.Padding(0);
             this.tableLayoutPanel1.Name = "tableLayoutPanel1";
             this.tableLayoutPanel1.Padding = new System.Windows.Forms.Padding(3);
-            this.tableLayoutPanel1.RowCount = 6;
+            this.tableLayoutPanel1.RowCount = 7;
             this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
             this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
             this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
             this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
             this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
             this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
-            this.tableLayoutPanel1.Size = new System.Drawing.Size(238, 137);
+            this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle());
+            this.tableLayoutPanel1.Size = new System.Drawing.Size(238, 160);
             this.tableLayoutPanel1.TabIndex = 0;
             // 
             // RemarksTextBox
@@ -102,7 +105,7 @@
             this.RemarksTextBox.MaxLength = 32;
             this.RemarksTextBox.Name = "RemarksTextBox";
             this.RemarksTextBox.Size = new System.Drawing.Size(160, 20);
-            this.RemarksTextBox.TabIndex = 10;
+            this.RemarksTextBox.TabIndex = 4;
             this.RemarksTextBox.WordWrap = false;
             // 
             // RemarksLabel
@@ -188,7 +191,7 @@
             // 
             // EncryptionSelect
             // 
-            this.EncryptionSelect.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
+            this.EncryptionSelect.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) 
             | System.Windows.Forms.AnchorStyles.Right)));
             this.EncryptionSelect.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
             this.EncryptionSelect.FormattingEnabled = true;
@@ -226,7 +229,7 @@
             this.OKButton.Margin = new System.Windows.Forms.Padding(3, 3, 3, 0);
             this.OKButton.Name = "OKButton";
             this.OKButton.Size = new System.Drawing.Size(75, 23);
-            this.OKButton.TabIndex = 8;
+            this.OKButton.TabIndex = 12;
             this.OKButton.Text = "OK";
             this.OKButton.UseVisualStyleBackColor = true;
             this.OKButton.Click += new System.EventHandler(this.OKButton_Click);
@@ -239,7 +242,7 @@
             this.MyCancelButton.Margin = new System.Windows.Forms.Padding(3, 3, 0, 0);
             this.MyCancelButton.Name = "MyCancelButton";
             this.MyCancelButton.Size = new System.Drawing.Size(75, 23);
-            this.MyCancelButton.TabIndex = 9;
+            this.MyCancelButton.TabIndex = 13;
             this.MyCancelButton.Text = "Cancel";
             this.MyCancelButton.UseVisualStyleBackColor = true;
             this.MyCancelButton.Click += new System.EventHandler(this.CancelButton_Click);
@@ -251,7 +254,7 @@
             this.DeleteButton.Margin = new System.Windows.Forms.Padding(3, 6, 0, 3);
             this.DeleteButton.Name = "DeleteButton";
             this.DeleteButton.Size = new System.Drawing.Size(80, 23);
-            this.DeleteButton.TabIndex = 7;
+            this.DeleteButton.TabIndex = 9;
             this.DeleteButton.Text = "&Delete";
             this.DeleteButton.UseVisualStyleBackColor = true;
             this.DeleteButton.Click += new System.EventHandler(this.DeleteButton_Click);
@@ -263,7 +266,7 @@
             this.AddButton.Margin = new System.Windows.Forms.Padding(0, 6, 3, 3);
             this.AddButton.Name = "AddButton";
             this.AddButton.Size = new System.Drawing.Size(80, 23);
-            this.AddButton.TabIndex = 6;
+            this.AddButton.TabIndex = 8;
             this.AddButton.Text = "&Add";
             this.AddButton.UseVisualStyleBackColor = true;
             this.AddButton.Click += new System.EventHandler(this.AddButton_Click);
@@ -276,8 +279,8 @@
             this.ServerGroupBox.Location = new System.Drawing.Point(178, 0);
             this.ServerGroupBox.Margin = new System.Windows.Forms.Padding(12, 0, 0, 0);
             this.ServerGroupBox.Name = "ServerGroupBox";
-            this.ServerGroupBox.Size = new System.Drawing.Size(249, 174);
-            this.ServerGroupBox.TabIndex = 6;
+            this.ServerGroupBox.Size = new System.Drawing.Size(249, 197);
+            this.ServerGroupBox.TabIndex = 0;
             this.ServerGroupBox.TabStop = false;
             this.ServerGroupBox.Text = "Server";
             // 
@@ -285,12 +288,11 @@
             // 
             this.ServersListBox.FormattingEnabled = true;
             this.ServersListBox.IntegralHeight = false;
-            this.ServersListBox.ItemHeight = 12;
             this.ServersListBox.Location = new System.Drawing.Point(0, 0);
             this.ServersListBox.Margin = new System.Windows.Forms.Padding(0);
             this.ServersListBox.Name = "ServersListBox";
             this.ServersListBox.Size = new System.Drawing.Size(166, 148);
-            this.ServersListBox.TabIndex = 5;
+            this.ServersListBox.TabIndex = 7;
             this.ServersListBox.SelectedIndexChanged += new System.EventHandler(this.ServersListBox_SelectedIndexChanged);
             // 
             // tableLayoutPanel2
@@ -313,7 +315,7 @@
             this.tableLayoutPanel2.RowStyles.Add(new System.Windows.Forms.RowStyle());
             this.tableLayoutPanel2.RowStyles.Add(new System.Windows.Forms.RowStyle());
             this.tableLayoutPanel2.RowStyles.Add(new System.Windows.Forms.RowStyle());
-            this.tableLayoutPanel2.Size = new System.Drawing.Size(427, 238);
+            this.tableLayoutPanel2.Size = new System.Drawing.Size(427, 261);
             this.tableLayoutPanel2.TabIndex = 7;
             // 
             // tableLayoutPanel6
@@ -326,7 +328,7 @@
             this.tableLayoutPanel6.Controls.Add(this.MoveDownButton, 1, 0);
             this.tableLayoutPanel6.Controls.Add(this.MoveUpButton, 0, 0);
             this.tableLayoutPanel6.Dock = System.Windows.Forms.DockStyle.Top;
-            this.tableLayoutPanel6.Location = new System.Drawing.Point(0, 211);
+            this.tableLayoutPanel6.Location = new System.Drawing.Point(0, 229);
             this.tableLayoutPanel6.Margin = new System.Windows.Forms.Padding(0);
             this.tableLayoutPanel6.Name = "tableLayoutPanel6";
             this.tableLayoutPanel6.RowCount = 1;
@@ -341,7 +343,7 @@
             this.MoveDownButton.Margin = new System.Windows.Forms.Padding(3, 6, 0, 3);
             this.MoveDownButton.Name = "MoveDownButton";
             this.MoveDownButton.Size = new System.Drawing.Size(80, 23);
-            this.MoveDownButton.TabIndex = 7;
+            this.MoveDownButton.TabIndex = 11;
             this.MoveDownButton.Text = "Move D&own";
             this.MoveDownButton.UseVisualStyleBackColor = true;
             this.MoveDownButton.Click += new System.EventHandler(this.MoveDownButton_Click);
@@ -353,7 +355,7 @@
             this.MoveUpButton.Margin = new System.Windows.Forms.Padding(0, 6, 3, 3);
             this.MoveUpButton.Name = "MoveUpButton";
             this.MoveUpButton.Size = new System.Drawing.Size(80, 23);
-            this.MoveUpButton.TabIndex = 6;
+            this.MoveUpButton.TabIndex = 10;
             this.MoveUpButton.Text = "Move &Up";
             this.MoveUpButton.UseVisualStyleBackColor = true;
             this.MoveUpButton.Click += new System.EventHandler(this.MoveUpButton_Click);
@@ -369,7 +371,7 @@
             this.tableLayoutPanel5.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle());
             this.tableLayoutPanel5.Controls.Add(this.ProxyPortTextBox, 1, 0);
             this.tableLayoutPanel5.Controls.Add(this.ProxyPortLabel, 0, 0);
-            this.tableLayoutPanel5.Location = new System.Drawing.Point(241, 174);
+            this.tableLayoutPanel5.Location = new System.Drawing.Point(241, 197);
             this.tableLayoutPanel5.Margin = new System.Windows.Forms.Padding(0);
             this.tableLayoutPanel5.Name = "tableLayoutPanel5";
             this.tableLayoutPanel5.Padding = new System.Windows.Forms.Padding(3);
@@ -389,7 +391,7 @@
             this.ProxyPortTextBox.MaxLength = 10;
             this.ProxyPortTextBox.Name = "ProxyPortTextBox";
             this.ProxyPortTextBox.Size = new System.Drawing.Size(113, 20);
-            this.ProxyPortTextBox.TabIndex = 4;
+            this.ProxyPortTextBox.TabIndex = 6;
             this.ProxyPortTextBox.WordWrap = false;
             // 
             // ProxyPortLabel
@@ -413,7 +415,7 @@
             this.tableLayoutPanel3.Controls.Add(this.MyCancelButton, 1, 0);
             this.tableLayoutPanel3.Controls.Add(this.OKButton, 0, 0);
             this.tableLayoutPanel3.Dock = System.Windows.Forms.DockStyle.Right;
-            this.tableLayoutPanel3.Location = new System.Drawing.Point(268, 209);
+            this.tableLayoutPanel3.Location = new System.Drawing.Point(268, 232);
             this.tableLayoutPanel3.Margin = new System.Windows.Forms.Padding(3, 3, 0, 3);
             this.tableLayoutPanel3.Name = "tableLayoutPanel3";
             this.tableLayoutPanel3.RowCount = 1;
@@ -431,7 +433,7 @@
             this.tableLayoutPanel4.Controls.Add(this.DeleteButton, 1, 0);
             this.tableLayoutPanel4.Controls.Add(this.AddButton, 0, 0);
             this.tableLayoutPanel4.Dock = System.Windows.Forms.DockStyle.Top;
-            this.tableLayoutPanel4.Location = new System.Drawing.Point(0, 174);
+            this.tableLayoutPanel4.Location = new System.Drawing.Point(0, 197);
             this.tableLayoutPanel4.Margin = new System.Windows.Forms.Padding(0);
             this.tableLayoutPanel4.Name = "tableLayoutPanel4";
             this.tableLayoutPanel4.RowCount = 1;
@@ -439,6 +441,16 @@
             this.tableLayoutPanel4.Size = new System.Drawing.Size(166, 32);
             this.tableLayoutPanel4.TabIndex = 8;
             // 
+            // OneTimeAuth
+            // 
+            this.OneTimeAuth.AutoSize = true;
+            this.OneTimeAuth.Location = new System.Drawing.Point(72, 137);
+            this.OneTimeAuth.Name = "OneTimeAuth";
+            this.OneTimeAuth.Size = new System.Drawing.Size(131, 17);
+            this.OneTimeAuth.TabIndex = 5;
+            this.OneTimeAuth.Text = "One-time authorization";
+            this.OneTimeAuth.UseVisualStyleBackColor = true;
+            // 
             // ConfigForm
             // 
             this.AcceptButton = this.OKButton;
@@ -505,6 +517,7 @@
         private System.Windows.Forms.TableLayoutPanel tableLayoutPanel6;
         private System.Windows.Forms.Button MoveDownButton;
         private System.Windows.Forms.Button MoveUpButton;
+        private System.Windows.Forms.CheckBox OneTimeAuth;
     }
 }
 
diff --git a/shadowsocks-csharp/View/ConfigForm.cs b/shadowsocks-csharp/View/ConfigForm.cs
index dc290249..b4b1b6bd 100755
--- a/shadowsocks-csharp/View/ConfigForm.cs
+++ b/shadowsocks-csharp/View/ConfigForm.cs
@@ -48,6 +48,7 @@ namespace Shadowsocks.View
             EncryptionLabel.Text = I18N.GetString("Encryption");
             ProxyPortLabel.Text = I18N.GetString("Proxy Port");
             RemarksLabel.Text = I18N.GetString("Remarks");
+            OneTimeAuth.Text = I18N.GetString("One-time authorization");
             ServerGroupBox.Text = I18N.GetString("Server");
             OKButton.Text = I18N.GetString("OK");
             MyCancelButton.Text = I18N.GetString("Cancel");
@@ -82,7 +83,8 @@ namespace Shadowsocks.View
                     server_port = int.Parse(ServerPortTextBox.Text),
                     password = PasswordTextBox.Text,
                     method = EncryptionSelect.Text,
-                    remarks = RemarksTextBox.Text
+                    remarks = RemarksTextBox.Text,
+                    one_time_auth = OneTimeAuth.Checked
                 };
                 int localPort = int.Parse(ProxyPortTextBox.Text);
                 Configuration.CheckServer(server);
@@ -115,6 +117,7 @@ namespace Shadowsocks.View
                 ProxyPortTextBox.Text = _modifiedConfiguration.localPort.ToString();
                 EncryptionSelect.Text = server.method ?? "aes-256-cfb";
                 RemarksTextBox.Text = server.remarks;
+                OneTimeAuth.Checked = server.one_time_auth;
             }
         }
 
diff --git a/shadowsocks-csharp/shadowsocks-csharp.csproj b/shadowsocks-csharp/shadowsocks-csharp.csproj
index 8200aa07..89389fab 100644
--- a/shadowsocks-csharp/shadowsocks-csharp.csproj
+++ b/shadowsocks-csharp/shadowsocks-csharp.csproj
@@ -205,6 +205,7 @@
     </None>
     <None Include="Data\abp.js.gz" />
     <None Include="Data\libsscrypto.dll.gz" />
+    <None Include="Data\libsscrypto2.dll.gz" />
     <None Include="Data\mgwz.dll.gz" />
     <None Include="Data\privoxy.exe.gz" />
     <None Include="Data\proxy.pac.txt.gz" />