John Graham-Cumming does not it pings me often, but when it does, I pay attention. His day job is CTO of security giant Cloudflare, but he’s also a layman tech historian guided by a righteous compass. He is perhaps best known for successfully leading a campaign to force the UK government to apologize to legendary computer scientist Alan Turing for prosecuting him for homosexuality and essentially bullying him to death. So when I was told by the DM to say it had a “hell of a story” – promising “one-shot pads! 8 bit computers! Flight attendants smuggle floppy disks full of random numbers into South Africa!” I replied.
The story he shared centers around Tim Jenkin, a former anti-apartheid activist. Jenkin grew up “like a normal racist white South African,” as he described it when I contacted him. But when Jenkin traveled abroad – beyond the filters of the police state – he learned about the brutal oppression in his home country and in 1974. offers his help to the African National Congress, the outlawed organization trying to overthrow the white regime. He returned to South Africa and became involved as an activist, distributing pamphlets. He has always had a penchant for gadgets and was adept at creating ‘leaflet bombs’ – devices placed in the street that, when triggered, shoot anti-government leaflets into the air to be dispersed by the wind. Unfortunately, he says, in 1978 “we were robbed.” Jenkin was sentenced to 12 years in prison.
Jenkin has a hacker’s mind – even as a child he played with gadgets, and as a teenager he took his motorcycle apart and put it back together. These skills proved his salvation. Working in the carpentry workshop, he creates models of the large keys that can unlock the prison doors. After months of secret carpentry and testing, he and two of his colleagues broke out of prison and eventually made it to London.
It was the early 1980s and the ANC’s efforts were weak. The problem was communications. Activists, especially ANC leaders, were under constant surveillance by South African officials. “The decision was made to bring leadership figures back into the country to be closer to the activists, but to do that they still had to liaise with outside countries,” says Jenkin, who was given a mandate to solve the problem . Elementary methods—such as invisible ink and sending codes via tone dialing—were not particularly effective. They wanted a communication system that was computerized and unbreakable. The plan was called Operation Vula.
Working in his small council flat in London’s Islington district – nicknamed GCHQ, after the top-secret British intelligence agency – Jenkins set about learning to code. These were the early days of computers and the equipment was laughably weak by today’s standards. Breakthroughs in public-key cryptography had appeared several years earlier, but there was no readily available implementation. And Jenkin was suspicious of prepackaged cryptosystems, fearing they could hide backdoors that would give governments access.
Using a Toshiba T1000 computer running an early version of MS-DOS, Jenkin wrote a system using the most secure form of crypto, a one-time pad that encoded messages character by character using a shared key that was as long as the message itself. Using the program, an activist can type a message on a computer and encrypt it with a floppy disk containing a one-time set of random numbers. The activist can then convert the encrypted text into audio signals and play them on a tape recorder to store them. Then, using a payphone, the activist could call, say, ANC leaders in London or Lusaka, Zambia, and play the recording. The receiver will use a modem with an acoustic coupler to pick up the sounds, translate them back into digital signals, and decode the message with the Jenkin program.
