C# DES加密解密

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace ConsoleApp1
{
    public class EncryptUtil
    {
        /// <summary>
        /// MD5加密碼字元串
        /// </summary>
        /// <param name="sInputString">消息體</param>
        /// <returns>MD5簽名字元</returns>
        public static string MD5Encrypt(string sInputString)
        {
            System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
            string encoded = BitConverter.ToString(md5.ComputeHash(Encoding.UTF8.GetBytes(sInputString))).Replace("-", "");
            return encoded;
        }

        /// <summary>
        /// DES加密
        /// </summary>
        /// <param name="sInputString">加密後的消息體</param>
        /// <param name="sKey">24位的密鑰</param>
        /// <returns>解密後的消息體</returns>
        public static string DESEncryptBase64(string sInputString, string sKey)
        {
            if (string.IsNullOrEmpty(sInputString) || string.IsNullOrEmpty(sKey) || sKey.Length != 24)
            {
                return string.Empty;
            }

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            des.Mode = CipherMode.ECB;
            des.Padding = PaddingMode.PKCS7;
            string key = sKey.Substring(0, 12);
            string iv = sKey.Remove(0, 12);
            byte[] byKey = Convert.FromBase64String(key);
            byte[] byIV = Convert.FromBase64String(iv);
            byte[] inputByteArray = Encoding.UTF8.GetBytes(sInputString);

            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            return Convert.ToBase64String(ms.ToArray());
        }

        /// <summary>
        /// DES解密
        /// </summary>
        /// <param name="sInputString">待加密消息體</param>
        /// <param name="sKey">24位的密鑰</param>
        /// <returns>加密後的消息體</returns>
        public static string DESDecryptBase64(string sInputString, string sKey)
        {
            if (string.IsNullOrEmpty(sInputString) || string.IsNullOrEmpty(sKey) || sKey.Length != 24)
            {
                return string.Empty;
            }

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            des.Mode = CipherMode.ECB;
            des.Padding = PaddingMode.PKCS7;

            string key = sKey.Substring(0, 12);
            string iv = sKey.Remove(0, 12);
            byte[] byKey = Convert.FromBase64String(key);
            byte[] byIV = Convert.FromBase64String(iv);
            byte[] inputByteArray = Convert.FromBase64String(sInputString);

            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, byIV), CryptoStreamMode.Write);

            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            Encoding encoding = new UTF8Encoding();
            return encoding.GetString(ms.ToArray());
        }

    }

}