Scientists to Secrets
The event began with Simon Singh giving a rather whistlestop tour through the basics of codes, ciphers and the inner workings of an Enigma machine. Impressively, he has his own Enigma machine, which has a rather lovely story behind it.
Martin Knight then went through the history of Bletchley Park and the personalities responsible for breaking the Enigma ‘code’ and various other mechanisms of secrecy employed by enemies of the British Empire. Harry Hinsley was 23 when he realised that German ‘trawlers’ carried copies of the Enigma codebooks – the key to cracking Enigma-encoded messages – and suggested that the Royal Navy might like to go and capture one of them.
Then Richard Aldrich took us through what happened to Bletchley Park after the War, ie its move to Cheltenham and transformation into GCHQ. There were some great stories about how the British embassy in Istanbul had 30 Royal Signallers, masquerading as ‘shipping clerks’ hiding on the top floor, stripped to the underwear in the oppressive heat, listening in to short-range radio communications across the Balkans. He has written a book about all of this and judging by his talk, it should be a good read.
Finally, Peter Knight took us through Quantum Cryptography for beginners. Even so it was slightly above my level of physics (I only did it for a year at Cambridge 17 years ago). He did mention the Colossus machine, which was built at Bletchley Park in order to break the Lorenz ciphers – the code machine eclipsed by Enigma in popular history but Colossus showed the ability of sheer computational power to break codes. The discussion of quantum cryptography was as you might expect but did throw up some lovely phraseology – “monogamous entanglement” describes how photons emitted at the same time remain correlated unless they are interfered with. Secure communications make use of this by sending a photon to the transmitter of a message and its receiver. If the photons do not correlate, something, or someone, has interfered with the message, which might simply mean they have read or attempted to read it.
I have a theory that a secret only qualifies as a secret if there is someone you are specifically not telling it to. Maybe that’s not much of a theory but it’s the kernal of a play I am writing, which made the evening pertinent in so many tangential ways. But the point was made that encryption can be done to maintain the integrity of information (eg to authenticate documents or operators) as well as its security (secrecy).
Ultimately, of course, the upshot of the evening was that for absolutely any system of cryptography, the easiest way to break it is to bribe the operators. The human element, naturally.