杏吧原创

HOW鈥橲 this for a cool recruitment campaign? In 2015, people on their way to work at tech companies in London paused, drawn by a curious message pressure-washed into the paving stones outside their offices. 鈥淕CH-WHO?鈥� the message ran, 鈥淭ECHNICAL OPPORTUNITIES鈥�, with a website address.

It was the work of GCHQ 鈥� the UK鈥檚 Government Communications Headquarters (before 1946, the Government Code and Cypher School). It is, and always has been, quite unnervingly on-trend. During the second world war, it wove recruitment adverts into crossword puzzles to attract the sort of people who could break the German Enigma and Lorentz ciphers.

Today, among other duties, cryptanalysts and other specialists help foil terrorist attacks (20 since the beginning of 2017), and still find time to tinker with Lego (their model of the Doughnut, GCHQ鈥檚 main building in Cheltenham, resembles a souped-up Millennium Falcon).

Only officially acknowledged since 1994, GCHQ is 100 years old this year and a new exhibition called Top Secret is a sort of celebration. It isn鈥檛 a history of GCHQ, but a series of snapshots which, while putting a positive spin on the work of the country鈥檚 intelligence agencies, still manages to ask pointed questions about cryptography, privacy, espionage and the right to know.

A map of trench communications lines and telephone points from the first world war introduces us to the messy world of communication in wartime. GCHQ was born out of a need to build a safe, coordinated system comprising electronically secure Fullerphones, ordinary telephones, telegraph signals, Morse and semaphore signalling, messenger dogs, carrier pigeons, lights, message-carrying rockets and dispatch messengers.

This daunting task hasn鈥檛 got any easier. But it has vanished from sight, as communications were first electrified, then digitised, before vanishing into a near impossible-to-comprehend cryptographic cloud.

During the second world war, GCHQ鈥檚 Bletchley Park base played a leading role in the development of information technology. Here the story is reduced to fascinating essentials: a copy of a German Lorentz machine, one of the few surviving components from an Alan Turing decoder known as a bombe, and, most evocative of all, a set of homemade rod-and-spindle calculating devices, used by human 鈥渃alculators鈥� early on in the war.

The story of UK-based Soviet agents Helen and Peter Kroger and the activities of the frighteningly effective Portland spy ring in the 1960s (they stole plans for the UK鈥檚 first nuclear submarine) stand in for the whole cold war. The couple鈥檚 elaborate equipment for hiding and transmitting secret messages is exhibited in a loose mock-up of their dreary suburban living room.

Volunteers are on hand to flesh out the stories. But don鈥檛 expect anything after 1983 to make sense. That was the year the internet was invented, scrambling our notions of privacy, anonymity and public interest. Now, every time we search, chat, date and shop, we feed vast data sets, from which commercial companies, states and rogue actors extract many kinds of profit.

There are now more internet-connected devices in the world than people, some almost as terrifying as the My Friend Cayla doll on show, condemned in Germany in 2017 as an 鈥渋llegal surveillance鈥� device. Look into its dead eyes and remember: no one can claim with confidence that they aren鈥檛 being watched.