/// 
    /// C#/PHP/JSP 3DES 加密与解密（只支持UTF-8编码）    /// 
    public class Crypto3DES    {        /// 
        /// 默认密钥        /// 
        private string Keys;        /// 
        /// 密钥与加密字符串不足8字符时的填充字符        /// 
        private char paddingChar = ' ';        /// 
        /// 实例化 Crypto3DES 类        /// 
        /// 密钥        public Crypto3DES(string key)        {            this.Keys = key;        }        /// 
        /// 获取密钥，不足8字符的补满8字符，超过8字符的截取前8字符        /// 
        /// 密钥        /// 
             private string GetKeyCode(string key)        {            if (key.Length > 8)                return key.Substring(0, 8);            else                return key.PadRight(8, paddingChar);        }        /// 
        /// 获取加密字符串，不足8字符的补满8字符        /// 
        /// The STR string.        /// 
             private string GetString(string strString)        {            if (strString.Length < 8)                return strString.PadRight(8, paddingChar);            return strString;        }        /// 
        /// 加密        /// 
        /// 加密字符串        /// 
             public string Encrypt(string strString)        {            try            {                strString = this.GetString(strString);                DESCryptoServiceProvider DES = new DESCryptoServiceProvider();                DES.Key = Encoding.UTF8.GetBytes(this.GetKeyCode(this.Keys));                DES.Mode = CipherMode.ECB;                DES.Padding = PaddingMode.Zeros;                ICryptoTransform DESEncrypt = DES.CreateEncryptor();                byte[] Buffer = Encoding.UTF8.GetBytes(strString);                return Convert.ToBase64String(DESEncrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));            }            catch (Exception ex) { return ex.Message; }        }        /// 
        /// 解密        /// 
        /// 解密字符串        /// 
             public string Decrypt(string strString)        {            try            {                DESCryptoServiceProvider DES = new DESCryptoServiceProvider();                DES.Key = Encoding.UTF8.GetBytes(this.GetKeyCode(this.Keys));                DES.Mode = CipherMode.ECB;                DES.Padding = PaddingMode.Zeros;                ICryptoTransform DESDecrypt = DES.CreateDecryptor();                byte[] Buffer = Convert.FromBase64String(strString);                return UTF8Encoding.UTF8.GetString(DESDecrypt.TransformFinalBlock(Buffer, 0, Buffer.Length)).Replace("\0", "").Trim();            }            catch (Exception ex) { return ex.Message; }        }        #region DESEnCode DESDeCode        /// 
        /// 加密 与Java通用加密        /// 
        /// 需要加密的字符        /// 密钥，8位的ASCII字符        /// 
             public string DESEnCode(string pToEncrypt)        {            if (string.IsNullOrEmpty(pToEncrypt)) return string.Empty;            try            {                pToEncrypt = System.Web.HttpContext.Current.Server.UrlEncode(pToEncrypt);                string key = this.Keys;                DESCryptoServiceProvider des = new DESCryptoServiceProvider();                byte[] inputByteArray = Encoding.GetEncoding("UTF-8").GetBytes(pToEncrypt);                des.Key = ASCIIEncoding.ASCII.GetBytes(key);                des.IV = ASCIIEncoding.ASCII.GetBytes(key);                System.IO.MemoryStream ms = new System.IO.MemoryStream();                CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);                cs.Write(inputByteArray, 0, inputByteArray.Length);                cs.FlushFinalBlock();                StringBuilder ret = new StringBuilder();                foreach (byte b in ms.ToArray())                {                    ret.AppendFormat("{0:X2}", b);                }                cs.Close();                cs.Dispose();                ms.Close();                ms.Dispose();                return ret.ToString();            }            catch (System.Exception ex)            {                return ex.Message;            }        }        /// 
         /// 解密数据  与Java通用解密        /// 
         /// 解密的字符        /// 密钥，8位的ASCII字符        /// 
              public string DESDeCode(string pToEncrypt)        {            if (string.IsNullOrEmpty(pToEncrypt)) return string.Empty;            try            {                DESCryptoServiceProvider des = new DESCryptoServiceProvider();                int len = pToEncrypt.Length / 2;                byte[] inputByteArray = new byte[len];                int x, i;                for (x = 0; x < len; x++)                {                    i = Convert.ToInt32(pToEncrypt.Substring(x * 2, 2), 16);                    inputByteArray[x] = (byte)i;                }                string key = this.Keys;                des.Key = ASCIIEncoding.ASCII.GetBytes(key);                des.IV = ASCIIEncoding.ASCII.GetBytes(key);                System.IO.MemoryStream ms = new System.IO.MemoryStream();                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);                cs.Write(inputByteArray, 0, inputByteArray.Length);                cs.FlushFinalBlock();                string ret = System.Web.HttpContext.Current.Server.UrlDecode(System.Text.Encoding.Default.GetString(ms.ToArray()));                cs.Close();                cs.Dispose();                ms.Close();                ms.Dispose();                return ret;            }            catch (System.Exception ex)            {                return ex.Message;            }        }        #endregion    }

Crypto3DES des = new Crypto3DES("key");