证书详解三篇

https://www.zhihu.com/question/24294477 

只看了上面一篇的第一个回答，懂了百分之八十。

https://yq.aliyun.com/articles/54155

https://www.zhihu.com/question/24294477/answer/93112599

https://www.zhihu.com/question/24484809/answer/70126366

单双向https认证：

http://blog.csdn.net/duanbokan/article/details/50847612