Base64加解密

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="encryptString"></param>
        /// <param name="keys">密钥(8位)</param>
        /// <returns></returns>
        public static string DESEncrypt(string encryptString, string keys)
        {
            using (System.Security.Cryptography.DESCryptoServiceProvider des = new System.Security.Cryptography.DESCryptoServiceProvider())
            {
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                des.Key = ASCIIEncoding.ASCII.GetBytes(keys);
                des.IV = ASCIIEncoding.ASCII.GetBytes(keys);
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                using (System.Security.Cryptography.CryptoStream cs = new System.Security.Cryptography.CryptoStream(ms, des.CreateEncryptor(), System.Security.Cryptography.CryptoStreamMode.Write))
                {
                    cs.Write(inputByteArray, 0, inputByteArray.Length);
                    cs.FlushFinalBlock();
                    cs.Close();
                }
                string str = Convert.ToBase64String(ms.ToArray());
                ms.Close();
                return str;
            }
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="decryptString"></param>
        /// <param name="keys"></param>
        /// <returns></returns>
        public static string DESDecrypt(string decryptString, string keys)
        {
            if (decryptString == string.Empty)
            {
                return "";
            }
            if (keys.Length < 8)
            {
                return "";
            }
            try
            {
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                using (System.Security.Cryptography.DESCryptoServiceProvider des = new System.Security.Cryptography.DESCryptoServiceProvider())
                {
                    des.Key = ASCIIEncoding.ASCII.GetBytes(keys);
                    des.IV = ASCIIEncoding.ASCII.GetBytes(keys);
                    System.IO.MemoryStream ms = new System.IO.MemoryStream();
                    using (System.Security.Cryptography.CryptoStream cs = new System.Security.Cryptography.CryptoStream(ms, des.CreateDecryptor(), System.Security.Cryptography.CryptoStreamMode.Write))
                    {
                        cs.Write(inputByteArray, 0, inputByteArray.Length);
                        cs.FlushFinalBlock();
                        cs.Close();
                    }
                    string str = Encoding.UTF8.GetString(ms.ToArray());
                    ms.Close();
                    return str;
                }
            }
            catch
            {
                return "";
            }
        }