David Cameron versus the universe

Yesterday, UK Prime Minister David Cameron made some incredibly stupid remarks.

Oh, right, let me narrow it down for you.

Yesterday, UK Prime Minister David Cameron made some incredibly stupid remarks about security on the internet.

The operative section is as follows:

“In extremis, it has been possible to read someone’s letter, to listen to someone’s call, to mobile communications … The question remains: are we going to allow a means of communications where it simply is not possible to do that?”

It’s nothing new for politicians to propose things that are unwise, that have unintended side effects or that are otherwise impractical or bad. But this is the first time that I can recall a senior politician actively committing to a policy that is literally impossible to implement.

Given a computer, a compiler and access to the internet, nothing can stop people having conversations which cannot be listened in on. It isn’t even really necessary to have the internet; sneakernet would do just as well.

Terrorist one uses commodity encryption to encrypt a message. He sends the encrypted text via the public internet. Terrorist two decrypts it using a key they have previously exchanged in person. Assuming they have both kept the key safe, there is no way of anyone else reading this message. This technology has been with us for well over a decade.

Encryption relies on certain properties of advanced mathematics. These properties cannot be changed on the whim of a politician any more than can gravity or space-time. While it is true that the technology industry has designed many faulty encryption algorithms, we have for some time been living in a world where the time required to crack even trivially available encryption on hardware from our wildest imaginations would be measured in terms of the lifetimes of stars.

Weakening encryption on consumer services like Snapchat or iMessage would clearly do nothing to prevent this sort of exchange, but it would certainly harm the everyday users of them. Security is hard enough to get right in the first place without having governments insert deliberate weaknesses into things.

There’s an election in four months, so naturally politicians will say things that will get them votes, even if it later turns out that they didn’t mean what they said, or that what they said made no sense, or that they’d been misquoted, or that there turned out to be no money left or whatever. Nothing new there.

What’s new here is that what David Cameron has proposed is literally impossible.