The art of cryptography is to make the cost of breaking the system exceed the value of the information protected.

Small habits, big changes.

历史的任务不是评判，而是理解。

The language of mathematics is universal, transcending cultural and linguistic barriers.

We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too.