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。

不学《诗经》，就无法表达自己的意思；不学习《礼记》，就无法在社会中立足。

Books are the quietest and most constant of friends; they are the most accessible and wisest of counselors, and the most patient of teachers.

快乐是最高的善，我们追求快乐，避免痛苦。

No man is useless in this world who lightens the burden of someone else.

现象是隐秘的本质所显现的外表。