http://blog.csdn.net/modianwutong/article/details/43059435
http://www.cnblogs.com/E7868A/archive/2012/11/16/2772240.html
http://wiki.ubuntu.org.cn/Openssl%E8%AF%81%E4%B9%A6%E7%AE%A1%E7%90%86
http://colinzhouyj.blog.51cto.com/2265679/1566250