Miller was steadfast. He wanted to get this information out, even if it was over his dead body.

In 1977, a group of brilliant researchers at MIT made an astonishing discovery—public-key cryptography.

It was a mathematical system for encrypting information so that only the intended recipient could read it. It would otherwise take millions of years for the world's most powerful supercomputers to crack.

Cryptography, or the practice of encoding information, is as old as civilization.