Should governments hold a key to every lock? The fight over encryption backdoors

Governments want to read criminals' messages, and strong encryption stops them. For three decades they have asked for some kind of lawful way in, and security researchers have kept raising objections. That tug of war is nicknamed the Crypto Wars: attempts by the US and allied governments to limit access to cryptography strong enough to thwart decryption by intelligence agencies such as the NSA, and the response of privacy advocates and civil libertarians.

An early weapon was export rules. A browser's "International Edition" got a deliberately weakened 40-bit key, and its encryption could be broken in days with a single personal computer. In 1993 the NSA promoted the Clipper chip, with a built-in backdoor for law enforcement. Every chip would hold a key given to the government in escrow, which critics called "key surrender". It was entirely defunct by 1996, and in 1994 Matt Blaze showed that the escrow could be bypassed.

The argument returned after the Snowden leaks. Around 2014 Apple and Google redesigned their phones so that they could not bypass the encryption themselves. In 2016 the FBI wanted Apple to write new software to unlock the iPhone of a San Bernardino shooter, and Apple declined. Apple's chief executive Tim Cook said the demand would set a precedent that could force any technology company to undermine its own products. The government later said a third party had helped, and withdrew its request.

The debate is still alive. A 1994 law already forces internet providers to build in access for authorities, and in 2024 the US government realized that China had been tapping communications in the US using that infrastructure. Critics see that as a door built for authorities being used by others; governments still argue, as the Clinton Administration did with Clipper, that access is essential for law enforcement to keep up with technology.