Re: Provided by?
"It is currently a jail-able offence to not reveal an encryption key when demanded"
Yes, but that costs money! This law is all about bulk surveillance and you can only do that if the cost per suspect (sorry, citizen) is minimal. The process of demanding encryption keys involves people actually going around doing the demanding together with lots of expensive paperwork. Feasible for hundreds of suspects, but not for tens of thousands.
I already have a VPN to a trusted overseas supplier (my mother-in-law) using only open source software which can't have been backdoored by HMG. Now, maybe one day PC Plod will turn up and demand the key. I will of course hand it over after slightly less than the maximum time allowed. They will spend ages searching for whatever interests them and presumably find nothing (yes, they could plant some evidence and convict me of any offence they like, but they could do that just as well last month). I will then re-build everything from scratch, create a new key and we can do the whole charade all over again if they want to spend some more money.
I don't mind GCHQ reading all my email and files provided that they have to work for it!