C# 加密算法实战：DES、RSA与MD5详解及源码

//DES.cs
//---------------------------
using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;
using System.IO;
using System.Security.Cryptography;

namespace Encrypt.Algorithm
{
    /// <summary>
    /// DES加密解密算法
    /// </summary>
    public class DES
    {
        /// <summary>
        /// DES加密算法
        /// sKey为8位或16位
        /// </summary>
        /// <param name="pToEncrypt">需要加密的字符串</param>
        /// <param name="sKey">密钥</param>
        /// <returns></returns>
        public string DesEncrypt(string pToEncrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.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();
            //return a;
        }
        /// <summary>
        /// DES解密算法
        /// sKey为8位或16位
        /// </summary>
        /// <param name="pToDecrypt">需要解密的字符串</param>
        /// <param name="sKey">密钥</param>
        /// <returns></returns>
        public string DesDecrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);