The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography

by Simon Singh

“Kerckhoffs’ Principle: The security of a cryptosystem must not depend on keeping secret the crypto-algorithm. The security depends only on keeping secret the key.”

Cryptanalysis could not be invented until a civilization had reached a sufficiently sophisticated level of scholarship in several disciplines, including mathematics, statistics and linguistics.

The really important question is whether quantum cryptography will arrive in time to save us from the threat of quantum computers, or whether there will be a privacy gap, a period between the development of quantum computers and the advent of quantum cryptography.