End-to-end encryption: Best ideas of the century

We all keep secrets. Whether you’re trying to protect messages to loved ones, business accounts, or vital government information, the technology that gives you peace of mind in our increasingly online world is end-to-end encryption (ETEE).

ETEE means that whoever provides your Internet connection or runs your email or video conferencing application cannot see your communications. In fact, they are encrypted on your device, then decrypted on the recipient’s device. During transmission, they constitute a meaningless string of impenetrable gibberish, so that no police force, spy agency, or criminally minded corporate member can demand, blackmail, or threaten its way.

Digital encryption does not depend on promises, but on immutable mathematics. The first useful form of encryption was made possible by the RSA algorithm, publicly described in 1977, which relies on the difficulty of finding the two prime factors that must be multiplied to create an extremely large number. Since then, other algorithms have used all kinds of obscure math to create other encryption codes that are difficult to crack.

But the power of ETEE lies not so much in exactly how it is implemented as in how Internet secrecy supports democracy and human rights around the world. “There are people in very dangerous parts of the world who literally depend on [encryption] to save their lives,” says Matthew Feeney of the UK-based privacy campaign group Big Brother Watch. Plus, even if you live in a place you consider a liberal democracy, these freedoms may be curtailed. “Those who say, ‘I’m a law-abiding citizen, I’ve done nothing wrong.’ [and I’ve nothing to hide]”, should get a history book and proceed with caution,” says Feeney.

Some governments may well hate ETEE because it prevents them from snooping in the same way that postal services and telephone networks allow. Indeed, successive British governments have tried to ban it, without success – most recently, in August last year, Prime Minister Keir Starmer announced an embarrassing U-turn after his government’s demands for Apple to install a backdoor were leaked.

We can’t say with certainty that no one has a way to breach ETEE, because intelligence agencies are not in the business of bragging about their capabilities, Feeney says. A looming threat is that quantum computers, which exploit principles of quantum mechanics such as superposition to solve complex problems that classical computers struggle with, could soon decipher the algorithms that ETEE currently depends on. Yet encryption has always been a game of cat and mouse, with new mathematical innovations arising as previous algorithms are weakened. “Governments are powerful institutions, but they have not yet outlawed mathematical laws,” says Feeney.