David Cameron says there should be no "means of communication" which "we cannot read"
It's very specific to communication, and reading between the lines, messaging, as opposed to something like HTTP communication between a bank and a customer. Don't get me wrong, it's still incredibly stupid, but the government will be able to reply to this petition with "we do not intend to ban encryption" and close it.
I think it's reasonable to assume that the terms would be more explicitly defined in an actual law.
As yourself used the term, how is "communication between a bank and a customer" not a form of "communication"?
I am not sure if it would be a good thing or not if this was the case, but leaving that aside laws are, in fact, liberally interpreted all the time, depending on your jurisdiction's legal tradition. This is why you can't hack the law; the interpretation of the law will change to fill in the gaps, provided that's what the justice system wants.
In any case, there is no law yet, so no language to examine.
In reality, the correct way to interpret laws is to think about their real purpose. Who benefits? What is the goal here?
The vast majority of laws have one of these two purposes: to enrich the government's cronies, or to cement the government's continued rule.
This just shows serious misinformation on your part.
ISIS recruitment would plummet to zero if people had to get TLS working before joining.
The average prospective terrorist / criminal etc isn't going to be able to set up TLS. If they encrypt their communications, the odds are it's going to be going via a third party. Next time you send an email, tell the recipient that from now on you're going to communicate directly by TLS, and they'll need to set up a server before you can talk to them again. I believe that most people will have considerable difficulty doing that.
So, you're reliant on third parties who constitute single points of failure and potential targets of legal action.
Individuals who can securely set up TLS (or PGP or whatever) for their own communications are sufficiently rare that they effectively don't matter.
For hosting provider setup, to domain name registration and TSL certificate generation there are thousands of online tutorials.
You don't need to be an expert or a developer to know how to setup TLS on a Wordpress blog.
This isn't really about stopping that though, it's about the snooping nanny state plain and simple.
I think you're severely underestimating the intelligence of people in general. If we're talking about ISIS, all it takes is one moderately experienced computer user to show everyone else how to use PGP.
And yet we find a bunch of supposedly encrypted stuff where the user did something wrong, leaving the stuff effectively unencrypted.
See also people uploading keys to github etc.
I suppose I omitted the step of copying and pasting your recipient's public key, but that's not especially conceptually difficult, either.
There's also keypair generation, which is the step that derails most people I think. Plus the fact that people have to grok the concept of public and private keys, and be able to distribute / not distribute them as appropriate. And revocation certificates. And public keyservers. And trust levels. Etc.
I do think an organised, disciplined group might manage to get PGP working as intended, but I doubt there are many such groups.
My point is, I doubt individuals implementing encryption have much to fear from whatever proposals may emerge from this. Maybe they will later. But it seems to me it's much more likely to target companies that offer/facilitate encrypted messaging.
Edit: Thanks to whoever just put my karma over 2000. Does anything exciting happen when you get to 2000 points?
Obviously, that's total conjecture, though.
Do you think the reason you use HTTPS to talk to your bank is to prevent the government from seeing your account balance?
I'd guess all the UK government would do is insist that, by law, all secured P2P messaging goes via a given cipher suite (one with a government backdoor/decryption key and, I guess, no perfect forward secrecy).
It's pretty conclusive how bad an idea it is, when all of the leading security experts in the world have said that this is impossible without weakening the entire security of the system.
Webmails, social medias or dating services are of a much greater interest to a nosy government.
Have you ever read about the various French Intel services after the revolution? Talk about convoluted. They trusted no one or even each other.