DESCryptoServiceProvider密码加密与解密

    /// <summary>
    /// 加密
    /// </summary>
    /// <param name="pToEncrypt"></param>
    /// <param name="sKey"></param>
    /// <returns></returns>
       public string Encrypt(string pToEncrypt, string sKey)
    {
        //访问数据加密标准(DES)算法的加密服务提供程序 (CSP) 版本的包装对象
        DESCryptoServiceProvider des = new DESCryptoServiceProvider();
        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　//建立加密对象的密钥和偏移量
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);　 //原文使用ASCIIEncoding.ASCII方法的GetBytes方法

        byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);//把字符串放到byte数组中

        MemoryStream ms = new MemoryStream();//创建其支持存储区为内存的流　
        //定义将数据流链接到加密转换的流
        CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
        cs.Write(inputByteArray, 0, inputByteArray.Length);
        cs.FlushFinalBlock();
        //上面已经完成了把加密后的结果放到内存中去

        StringBuilder ret = new StringBuilder();
        foreach (byte b in ms.ToArray())
        {
            ret.AppendFormat("{0:X3}", b);
        }
        ret.ToString();
        return ret.ToString();
    }