验证码 原理 破解
reference:
http://blog.youkuaiyun.com/zollty/article/details/7561052
http://blog.youkuaiyun.com/lywybo/article/details/5822233
http://blog.youkuaiyun.com/tongdoudpj/article/details/1924300
http://blog.youkuaiyun.com/yysdsyl/article/details/5329631
reference:
http://blog.youkuaiyun.com/zollty/article/details/7561052
http://blog.youkuaiyun.com/lywybo/article/details/5822233
http://blog.youkuaiyun.com/tongdoudpj/article/details/1924300
http://blog.youkuaiyun.com/yysdsyl/article/details/5329631