这篇是我之前做项目时用到的，写了个小demo，发在原来的一个博客里。因为博客空间在国外经常被墙，今天把之前写的一些东西搬到这里来。

迅雷，快车旋风链接编码解码C#源代码

在做一个项目时，有要求用到下载工具下载，于是上网找了找，找到了这些链接的加密规则，自己写了几个转换方法

写的有点急，可能不太完善，若您在使用中发现问题，烦请留言给我指出，谢谢！

using System; 
using System.Text; 
/*
 * Author:大宝http://dabao.im,http://dabao2010.blog.51cto.com
 * Desc:迅雷，快车，旋风链接编码解码
 */
namespace Base64Url 
{ 
class Program 
{ 
        #region 静态常量
/// <summary>迅雷 thunder://</summary>
publicconststring _thunder = "Thunder://"; 
/// <summary>快车 flashget://</summary>
publicconststring _flashget = "Flashget://"; 
/// <summary>QQ旋风 qqdl://</summary>
publicconststring _qqdl = "Qqdl://"; 
        #endregion
staticvoid Main(string[] args) 
{ 
string url = ""; 
url = "thunder://QUFmdHA6Ly82OjZAZnRwLjY2eXMub3JnOjQ1MDgv44CQ6L+F6Zu35LiL6L29d3d3LmR5MTMxLmNvbeOAkVjmiJjorabliY3kvKDvvJrph6HliJrni7xCROS4reiLseWPjOWtlzEyODDpq5jmuIUucm12Ylpa"; 
//url = "Flashget://W0ZMQVNIR0VUXWh0dHA6Ly9ibG9nLnhpYW9odW9jaGFpLm5ldFtGTEFTSEdFVF0=&xiaohuochai";
//url="Qqdl://aHR0cDovL2Jsb2cueGlhb2h2b2NoYWkubmV0";
string url2 = "http://xiaohuochai.net"; 
string thunder = ""; 
string flashget = ""; 
string qqdl = ""; 
//编码
thunder = EncodeUrlToBase64(url2, LinkType.Thunder); 
flashget = EncodeUrlToBase64(url2, LinkType.Flashget); 
qqdl = EncodeUrlToBase64(url2, LinkType.Qqdl); 
Console.Write(thunder + "\r\n" + flashget + "\r\n" + qqdl + "\r\n"); 
//解码
string result = "您输入的地址可能不是迅雷，快车，旋风中的任何一种！"; 
if (url.StartsWith(_thunder, true, null))//迅雷
result = DecodeUrlFromBase64(url.Remove(0, _thunder.Length), LinkType.Thunder); 
if (url.StartsWith(_flashget, true, null))//快车
result = DecodeUrlFromBase64(url.Remove(0, _flashget.Length), LinkType.Flashget); 
if (url.StartsWith(_qqdl, true, null))//QQ旋风
result = DecodeUrlFromBase64(url.Remove(0, _qqdl.Length), LinkType.Qqdl); 
Console.Write(result); 
Console.ReadLine(); 
} 
        #region 编码&解码
        #region 编码
/// <summary>
/// 编码URL
/// </summary>
/// <param name="url">原生URL</param>
protectedstaticstring EncodeUrlToBase64(string url, LinkType linktype) 
{ 
string enurl = ""; 
string tempUrl = ""; 
switch (linktype) 
{ 
case LinkType.Thunder: 
tempUrl = "AA" + url + "ZZ"; 
enurl = _thunder + EnCodeUrl(tempUrl); 
break; 
case LinkType.Flashget: 
tempUrl = "[FLASHGET]" + url + "[FLASHGET]"; 
enurl = _flashget + EnCodeUrl(tempUrl) + "&xiaohuochai";//&后为用户自定义信息，具体什么用还不清楚
break; 
case LinkType.Qqdl: 
enurl = _qqdl + EnCodeUrl(url); 
break; 
default: 
break; 
} 
return enurl; 
} 
privatestaticstring EnCodeUrl(string tempUrl) 
{ 
byte[] bytes; string enurl; 
bytes = Encoding.Default.GetBytes(tempUrl); 
enurl = Convert.ToBase64String(bytes); 
return enurl; 
} 
        #endregion
        #region 解码
/// <summary>
/// 链接解码
/// </summary>
/// <param name="baseurl">链接</param>
protectedstaticstring DecodeUrlFromBase64(string baseurl, LinkType linktype) 
{ 
string deurl = ""; 
switch (linktype) 
{ 
case LinkType.Thunder: 
deurl = DecodeUrl(baseurl); 
deurl = deurl.Remove(0, 2); 
deurl = deurl.Remove(deurl.Length - 2); 
break; 
case LinkType.Flashget: 
deurl = DecodeUrl(baseurl.Remove(baseurl.LastIndexOf('&'))); 
deurl = deurl.Remove(0, 10); 
deurl = deurl.Remove(deurl.Length - 10); 
break; 
case LinkType.Qqdl: 
deurl = DecodeUrl(baseurl); 
break; 
default: 
break; 
} 
return deurl; 
} 
privatestaticstring DecodeUrl(string baseurl) 
{ 
byte[] bytes; 
string deurl; 
bytes = Convert.FromBase64String(baseurl); 
deurl = Encoding.UTF8.GetString(bytes); 
return deurl; 
} 
        #endregion
        #endregion
} 
/// <summary>
/// 链接类型
/// </summary>
enum LinkType 
{ 
/// <summary>迅雷</summary>        
Thunder, 
/// <summary>快车</summary>
Flashget, 
/// <summary>QQ旋风</summary>
Qqdl 
} 
}