原文链接：http://www.cnblogs.com/CielWater/p/4253099.html

    /// <summary>
    /// Des和3Des算法
    /// </summary>
    public class Des
    {
        /// <summary>
        /// Des加密
        /// </summary>
        /// <param name="pToEncrypt">明文</param>
        /// <param name="sKey">密钥</param>
        /// <returns></returns>
        public static string DESEnCode(string pToEncrypt, string sKey)
        {
            pToEncrypt = HttpContext.Current.Server.UrlEncode(pToEncrypt);
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.GetEncoding("UTF-8").GetBytes(pToEncrypt);


            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new 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);
            }
            ret.ToString();
            return ret.ToString();
        }
        /// <summary>
        /// 3Des加密(密钥不能每8位重复，例如：123456781234567812345678，如果这样则算法退化为Des，C#会检测，不能使用)
        /// </summary>
        /// <param name="a_strString">明文</param>
        /// <param name="a_strKey">密钥</param>
        /// <returns></returns>
        public string Decrypt3DES(string a_strString, string a_strKey)
        {
            TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();

            DES.Key = ASCIIEncoding.ASCII.GetBytes(a_strKey);
            DES.Mode = CipherMode.ECB;
            DES.Padding = System.Security.Cryptography.PaddingMode.PKCS7;

            ICryptoTransform DESDecrypt = DES.CreateEncryptor();

            string result = "";
            try
            {
                byte[] Buffer = Convert.FromBase64String(a_strString);
                result = ASCIIEncoding.ASCII.GetString(DESDecrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));
            }
            catch (Exception e)
            {

            }
            return result;
        }
        /// <summary>
        /// Des解密
        /// </summary>
        /// <param name="encryptedString">密文</param>
        /// <param name="key">密钥</param>
        /// <returns></returns>
        public string Decrypt(string encryptedString, string key)
        {
            byte[] btKey = Encoding.UTF8.GetBytes(key);

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            des.Key = ASCIIEncoding.ASCII.GetBytes(key);
            des.Mode = CipherMode.ECB;
            des.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
            using (MemoryStream ms = new MemoryStream())
            {
                byte[] inData = Convert.FromBase64String(encryptedString);
                try
                {
                    using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(inData, 0, inData.Length);

                        cs.FlushFinalBlock();
                    }

                    return Encoding.UTF8.GetString(ms.ToArray());
                }
                catch
                {
                    return encryptedString;
                }
            }
        }
        /// <summary>
        /// 3Des解密(密钥不能每8位重复，例如：123456781234567812345678，如果这样则算法退化为Des，C#会检测，不能使用)
        /// </summary>
        /// <param name="a_strString">密文</param>
        /// <param name="a_strKey">密钥</param>
        /// <returns></returns>
        public string Decrypt3DES(string a_strString, string a_strKey)
        {
            TripleDESCryptoServiceProvider DES = new TripleDESCryptoServiceProvider();

            DES.Key = ASCIIEncoding.ASCII.GetBytes(a_strKey);
            DES.Mode = CipherMode.ECB;
            DES.Padding = System.Security.Cryptography.PaddingMode.PKCS7;

            ICryptoTransform DESDecrypt = DES.CreateDecryptor();

            string result = "";
            try
            {
                byte[] Buffer = Convert.FromBase64String(a_strString);
                result = ASCIIEncoding.ASCII.GetString(DESDecrypt.TransformFinalBlock(Buffer, 0, Buffer.Length));
            }
            catch (Exception e)
            {

            }
            return result;
        }
    }

 

转载于:https://www.cnblogs.com/CielWater/p/4253099.html