密码学是关于在存在对手的情况下进行通信的。

老虎的尾巴不会长在狸猫身上，象牙也不会长在老鼠的口中。这句话是说小人是不会做出高尚的事情的。

The true artist helps the world by revealing mystic truths.

编写错误的程序要比理解正确的程序容易。

I was no good at art, so I thought I'd better be an artist.

If the job has been correctly done when a common stock is purchased, the time to sell it is—almost never.