Your key point here, that well overseen, targeted surveillance is not necessarily a bad thing is correct (although not the angle I was originally going for ;)) but I do have a few points to make.
3 hours ago, evildictaitor wrote
Similarly it's important that the police can decrypt the hard-drive of pedophiles to identify victims and to prove guilt
Heh, that particular one is an insoluble problem.
The penalty for failing to decrypt data on demand is (rightly) far lower than the penalty for being a paedophile. The paedophile will just take the three years jail time for failing to decrypt their data. And in the US such a law is constitutionally impossible if the holder of the decryption key is also the suspect (self incrimination).
There's no way to technically weaken encryption only for the authorities and not for the bad guys either. And, even with the best oversight in the world, there's no way trust that that information wouldn't leak to the bad guys (especially when we've seen how easily Snowden was able to walk off with their deepest secrets).
There's also a lot of chest-thumping and fist-shaking by crypto-anarchists who seem to forget that it was always thus. Western governments have always been able to investigate you for crimes, and only in the past few years has anonymity and military-grade encryption been the automatic choice of the law-abiding populace, rather than the exclusive preserve of legitimate government targets like terrorists and foreign governments.
The reality is things have changed as much in the authorities' favour as the cryptanarchists'. They could investigate you in the past but they had to put the resources in to having agents follow you or open your post. They had to come and bug your house. The pragmatic and cost barriers thus created acted as a form of oversight - the wouldn't investigate a probably innocent person on the off chance; they couldn't afford to watch everyone for criminality. It forced the presumption of innocence. Records didn't exist unless they were specially made - they couldn't go to the Royal Mail and find everyone who'd written to me in the last six months because that data wasn't recorded (heck, snail mail is inherently more anonymous than email anyway).
Mass communication enabled mass surveillance. Suddenly they could easily see and record the "metadata" and, in some cases, content of everyone's communication. And store this for the future. Vast archives of our communications are held, for the first time, by third parties who can be compelled to give them up without our knowledge. (I won't go into why this is bad here, I'll take that as a given.)
The suggestion that we're just giving authorities the digital equivalents of powers they've always held is complete, total bollocks. It's simply not true. In fact many of the technological solutions proposed will simply return things to an earlier state of affairs. Widespread encryption won't stop the authorities doing what they do; it will just force them to target their resources. They'll be forced to go through courts and get orders under the relevant legislation (e.g. RIPA in the UK) to decrypt data or invest time and effort in cracking your encrypted communications.
And in fact they'll still be better off because they can get your last decade of emails from GMail rather than just whatever they can get after they start intercepting your communications.
We run the very serious risk over the next few years of swinging really far towards technical safeguards which actually undermine the ability of police to investigate crimes or provide evidence after devices are seized.
And they'll have brought that on themselves by proving themselves untrustworthy. Frankly any serious criminal will have been taking effective technical countermeasures already.
And central to that is the misinformation by some of the media to conflate "collection" of large quantities of data with "surveillance" of large numbers of people, and to conflate "massive capabilities" with "excessive use of those capabilities".
This is something the state has NEVER had before. It's not the normal historic state of affairs. You're painting a false distinction too. What about if the computer runs a bunch of algorithms on that data to decide who to pass onto the humans to look at, does that count as surveillance? Does it count as surveillance if humans look at it but never act on it? Is CCTV not surveillance provided nobody reviews the tapes?
In fact I'd have thought "collection of data about someone or something" is more or less the dictionary definition of surveillance.
They have a database that tells them what my daily routine is, who I talk to, what I think. In the wrong hands that's incredibly powerful, and incredibly dangerous.
EDIT: @bondsbw: tbh you said it better than I did. Especially the second half of your reply.