8 A Quantum Leap into the Future

For two thousand years, codemakers have fought to preserve secrets while codebreakers have tried their best to reveal them. It has always been a neck-and-neck race, with codebreakers battling back when codemakers seemed to be in command, and codemakers inventing new and stronger forms of encryption when previous methods had been compromised. The invention of public key cryptography and the political debate that surrounds the use of strong cryptography bring us up to the present day, and it is clear that the cryptographers are winning the information war. According to Phil Zimmermann, we live in a golden age of cryptography: “It is now possible to make ciphers in modern cryptography that are really, really out of reach of all known forms of cryptanalysis. And I think it’s going to stay that way.” Zimmermann’s view is supported by William Crowell, Deputy Director of the NSA: “If all the personal computers in the world-approximately 260 million computers-were to be put to work on a single PGP encrypted message, it would take on average an estimated 12 million times the age of the universe to break a single message.”

Previous experience, however, tells us that every so-called unbreakable cipher has, sooner or later, succumbed to cryptanalysis. The Vigenère cipher was called “le chiffre indéchiffrable,” but Babbage broke it; Enigma was considered invulnerable, until the Poles revealed its weaknesses. So, are cryptanalysts on the verge of another breakthrough, or is Zimmermann right? Predicting future developments in any technology is always a precarious task, but with ciphers it is particularly risky. Not only do we have to guess which discoveries lie in the future, but we also have to guess which discoveries lie in the present. The tale of James Ellis and GCHQ warns us that there may already be remarkable breakthroughs hidden behind the veil of government secrecy.

This final chapter examines a few of the futuristic ideas that may enhance or destroy privacy in the twenty-first century. The next section looks at the future of cryptanalysis, and one idea in particular that might enable cryptanalysts to break all today’s ciphers. In contrast, the final section of the book looks at the most exciting cryptographic prospect, a system that has the potential to guarantee absolute privacy.