密码数据加密

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

namespace DAL
{
    public sealed class MD5Hashing
    {
        private static MD5 md5 = MD5.Create();
        private static string sKey = GenerateKey();

        private MD5Hashing()
        {
        }
        /**/
        /// <summary>
        /// 将字符串加密
        /// </summary>
        /// <param name="sourceString">需要加密的字符串</param>
        /// <returns>MD5加密后字符串</returns>
        public static string HashString(string sourceString)
        {
            return HashString("gb2312", sourceString);
        }
        /**/
        /// <summary>
        /// 字符串Hash加密
        /// </summary>
        /// <param name="codeName">编码类型</param>
        /// <param name="sourceString">需要加密的字符串</param>
        /// <returns>MD5加密后字符串</returns>
        public static string HashString(string codeName, string sourceString)
        {
            byte[] source = md5.ComputeHash(Encoding.GetEncoding(codeName).GetBytes(sourceString));
            StringBuilder sBuilder = new StringBuilder();
            for (int i = 0; i < source.Length; i++)
            {
                sBuilder.Append(source[i].ToString("x"));
            }
            return sBuilder.ToString();
        }
　　　　　　//方法(二)
        // 创建Key
        public static string GenerateKey()
        {
            DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create();
            return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
        }
        ///MD5加密
        public static string MD5Encrypt(string pToEncrypt)
        {
            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);
            }
            return ret.ToString();
        }
　　　　　
        ///MD5解密
        public static string MD5Decrypt(string pToDecrypt)
        {
            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);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();

            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }
    }
}