Cryptonomicon

by Neal Stephenson

The longer the key you are trying to generate, the longer this takes. Randy is trying to generate one that is ridiculously long. He has pointed out to Avi, in an encrypted e-mail message, that if every particle of matter in the universe could be used to construct one single cosmic supercomputer, and this computer was put to work trying to break a 4096-bit encryption key, it would take longer than the lifespan of the universe. “Using today’s technology,” Avi shot back, “that is true. But what about quantum computers? And what if new mathematical techniques are developed that can simplify the factoring of large numbers?” “How long do you want these messages to remain secret?” Randy asked, in his last message before leaving San Francisco. “Five years? Ten years? Twenty-five years?” After he got to the hotel this afternoon, Randy decrypted and read Avi’s answer. It is still hanging in front of his eyes, like the afterimage of a strobe: I want them to remain secret for as long as men are capable of evil.