字符串的加密与解密（一）

         /// <summary>
         /// 使用MD5加密字符串
          /// </summary>
        /// <param name="source">待加密的字符串</param>
        /// <returns>加密后的字符串</returns>
        private static string MD5Encrypt(string source)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] t = md5.ComputeHash(Encoding.ASCII.GetBytes(source));
            StringBuilder sb = new StringBuilder(32);
            for (int i = 0; i < t.Length; i++)
            {
                sb.Append(t[i].ToString("x").PadLeft(2, ‘0‘));
            }
            return sb.ToString().ToUpper();
        }