md5helper.cs

是一个简易的聊天系统

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

namespace Utility
{
    public class MD5Helper
    {
        public MD5Helper() { }

        #region
        /// <summary>
        /// MD5加密字符串与System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile一致
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string MD5Encrypt(string data)
        {
            byte[] b = Encoding.Default.GetBytes(data);
            return MD5Encrypt(b);
        }
        /// <summary>
        /// MD5加密字符串与System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile一致
        /// </summary>
        /// <<param name="data"></param>
        /// <returns></returns>
        public static string MD5Encrypt(byte[] data)
        {
            data = new MD5CryptoServiceProvider().ComputeHash(data);
            string ret = "";
            for (int i = 0; i < data.Length; i++)
            {
                ret += data[i].ToString("x").PadLeft(2, '0');
            }
            return ret.ToUpper(); ;
        }
        #endregion
    }
         /// <summary>
    /// Rijndael
    /// </summary>
    public class Rijndael_
        {

            private RijndaelManaged myRijndael;
            public string Key;
            public string IV;
            /**/
            /// <summary>
            /// 对称加密类的构造函数
            /// </summary>
            public Rijndael_(string key)
            {
                myRijndael = new RijndaelManaged();
                //key = "7H6598zahdgd765%4%$#^$hjh76";
                Key = key;
                IV = "67^%*(&(*Ghg7!rNIfb&95Gd$jhWk7&!hg4ui%$hjk";
            }
            /**/
            /// <summary>
            /// 对称加密类的构造函数
            /// </summary>
            public Rijndael_(string key, string iv)
            {
                myRijndael = new RijndaelManaged();
                Key = key;
                IV = iv;
            }
            /**/
            /// <summary>
            /// 获得密钥
            /// </summary>
            /// <returns>密钥</returns>
            private byte[] GetLegalKey()
            {
                string sTemp = Key;
                myRijndael.GenerateKey();
                byte[] bytTemp = myRijndael.Key;
                int KeyLength = bytTemp.Length;
                if (sTemp.Length > KeyLength)
                    sTemp = sTemp.Substring(0, KeyLength);
                else if (sTemp.Length < KeyLength)
                    sTemp = sTemp.PadRight(KeyLength, ' ');
                return ASCIIEncoding.ASCII.GetBytes(sTemp);
            }
            /**/
            /// <summary>
            /// 获得初始向量IV
            /// </summary>
            /// <returns>初试向量IV</returns>
            private byte[] GetLegalIV()
            {
                string sTemp = IV;
                myRijndael.GenerateIV();
                byte[] bytTemp = myRijndael.IV;
                int IVLength = bytTemp.Length;
                if (sTemp.Length > IVLength)
                    sTemp = sTemp.Substring(0, IVLength);
                else if (sTemp.Length < IVLength)
                    sTemp = sTemp.PadRight(IVLength, ' ');
                return ASCIIEncoding.ASCII.GetBytes(sTemp);
            }
            /**/
            /// <summary>
            /// 加密方法
            /// </summary>
            /// <param name="Source">待加密的串</param>
            /// <returns>经过加密的串</returns>
            public string Encrypt(string Source)
            {
                try
                {
                    byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);
                    MemoryStream ms = new MemoryStream();
                    myRijndael.Key = GetLegalKey();
                    myRijndael.IV = GetLegalIV();
                    ICryptoTransform encrypto = myRijndael.CreateEncryptor();
                    CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
                    cs.Write(bytIn, 0, bytIn.Length);
                    cs.FlushFinalBlock();
                    ms.Close();
                    byte[] bytOut = ms.ToArray();
                    return Convert.ToBase64String(bytOut);
                }
                catch (Exception ex)
                {
                    throw new Exception("在文件加密的时候出现错误！错误提示： \n" + ex.Message);
                }
            }
            /**/
            /// <summary>
            /// 解密方法
            /// </summary>
            /// <param name="Source">待解密的串</param>
            /// <returns>经过解密的串</returns>
            public string Decrypt(string Source)
            {
                try
                {
                    byte[] bytIn = Convert.FromBase64String(Source);
                    MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length);
                    myRijndael.Key = GetLegalKey();
                    myRijndael.IV = GetLegalIV();
                    ICryptoTransform encrypto = myRijndael.CreateDecryptor();
                    CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
                    StreamReader sr = new StreamReader(cs);
                    return sr.ReadToEnd();
                }
                catch (Exception ex)
                {
                    throw new Exception("在文件解密的时候出现错误！错误提示： \n" + ex.Message);
                }
            }
        }

    
}