url编码

方案一
： 
  Security sec = new Security();
  传递
  http:localhost/book.aspx?key="+sec.Encrypt(key, "cccccccc")+"
  获取
  string key= sec.Decrypt(Request.QueryString["key"].ToString(), "cccccccc");
方案二
：
传递
  http:localhost/book.aspx?key="+Server.UrlEncode(key)+"
 获取
  string key= Server.UrlDecode(Request.QueryString["key"].ToString());