DES加密解密

    /// <summary>
    /// 加密類
    /// <para>Date:2012-04-23 PM.</para>
    /// </summary>
    public class Encrypt
    {
        /// <summary>
        /// 默認密鑰向量.
        /// </summary>
        private static readonly byte[] Keys = { 0xAB, 0xCD, 0xEF, 0x68, 0xDB, 0xFA, 0x01, 0xE2 };

        private Encrypt() { }

        /// <summary>
        /// 創建加密類對象.
        /// </summary>
        public static Encrypt CreateCryptoServiceProvider()
        {
            return new Encrypt();
        }

        /// <summary>
        /// DES加密.
        /// </summary>
        /// <param name="_EncryptStr">待加密字符串.</param>
        /// <param name="_EncryptKey">加密密鑰. 8位</param>
        /// <returns></returns>
        public String DESEncrypt(String _EncryptStr,String _EncryptKey)
        {
            try
            {
                byte[] RogerKey = Encoding.Default.GetBytes(_EncryptKey.Substring(0, 8));
                byte[] RogerIV = Keys;
                byte[] RogerString = Encoding.Default.GetBytes(_EncryptStr);
                DES RogerDES = new DESCryptoServiceProvider();
                MemoryStream RogerMs = new MemoryStream();
                CryptoStream RogerCs = new CryptoStream(RogerMs, RogerDES.CreateEncryptor(RogerKey, RogerIV), CryptoStreamMode.Write);
                RogerCs.Write(RogerString, 0, RogerString.Length);
                RogerCs.FlushFinalBlock();
                String result = BitConverter.ToString(RogerMs.ToArray()).Replace("-", string.Empty);
                return result;
            }
            catch (Exception)
            {
                return _EncryptStr;
            }
        }

        /// <summary>
        /// DES解密.
        /// </summary>
        /// <param name="_DecryptStr">等解密的字符串.</param>
        /// <param name="_DecryptKey">解密密鑰. 8位</param>
        /// <returns></returns>
        public String DESDecrypt(String _DecryptStr, String _DecryptKey)
        {
            try
            {
                byte[] RogerKey = Encoding.Default.GetBytes(_DecryptKey.Substring(0, 8));
                byte[] RogerIV = Keys;

                int blocks = _DecryptStr.Length / 2;
                byte[] EncryptByteData = new byte[blocks];
                String tempItem = null;
                for (int i = 0; i < blocks; i++)
                {
                    tempItem = _DecryptStr.Substring(i * 2, 2);
                    EncryptByteData[i] = byte.Parse(tempItem, System.Globalization.NumberStyles.HexNumber);
                }

                DES RogerDES = new DESCryptoServiceProvider();
                MemoryStream RogerMs = new MemoryStream();
                CryptoStream RogerCs = new CryptoStream(RogerMs, RogerDES.CreateDecryptor(RogerKey, RogerIV), CryptoStreamMode.Write);
                RogerCs.Write(EncryptByteData, 0, EncryptByteData.Length);
                RogerCs.FlushFinalBlock();
                String result = Encoding.Default.GetString(RogerMs.ToArray());
                return result;
            }
            catch (Exception)
            {
                return _DecryptStr;
            }
        }
    }