如果你不能保持灵活的思路，就会抓狂，忽视解决问题的其他可能性。

I went to the woods because I wanted to live deliberately. I wanted to live deep and suck out all the marrow of life. To put to rout all that was not life. And not, when I had come to die, discover that I had not lived.

除了诱惑，我什么都能抵抗。

密码学的艺术是使破解系统的成本超过受保护信息的价值。