They can hire a safe-cracker, but if they can't find one that can break in to your safe, you still don't have to give up the combination and the cops are out of luck.
Quite. But how realistic is this? How many safes out there can the police not get cracked? Its a theoretical limitation with no real implication on actual law enforcement activity.
Contrast this with "everybody and their un-crackable cellphone".
If someone made a physical safe the cops couldn't break into, and people were buying them by the millions law enforcement would be in a similar tizzy about it. Except I doubt that can happen, nothing one can build can't be ground down again. And the cost of such a safe would be extreme.
Contrast with encryption where the cost of encryption is negligible, and uncrackable. (aka "free with 2 year contract")
Encrypted data is the same. They can't force you to give them the passphrase but they can hire someone to try and crack it. If no one can, the cops are out of luck.
Exactly. But they aren't ok with being "out of luck" so often.
What if I had a paper diary and I wrote it in my own language(encryption)?
You'd be surprised how easy it would be to crack in practice. In most cases invented languages would be little more than some window dressing on an existing language, with some simple ciphers etc. Couple that with other relatively detailed knowledge they have about your movements and activities and they almost have a Rosetta stone.
But sure, we can hypothesize you invented the equivalent of martian for the sake of argument, and nobody can make anything of it.
The cops would be out of luck.
Ok, how many people do you think in the world are inventing the equivalent of martian to write their criminal diaries? Are even capable of it? How many police investigations have been hampered by it?
The police don't have a problem with this, because it practically NEVER happens.
The issue they have with encryption is that every criminal from a purse snatcher to the head of the Yakuza uses computers, tablets, smartphones, etc. So its an actual obstacle to actual investigations instead of a hypothetical issue that never happens.
I don't see how you have a problem with any of this.
In an ideal world, I'd want police to be able to break into an encrypted device with a warrant. Why wouldn't I want that? But for better or worse, in the real world, for the first time ever we have somewhere we can put our documents that is easy, convenient, inexpensive, and is secure enough to keep even global super powers from getting in with all their resources combined. Never mind the local police detachment.
I don't have a "problem" with it, in the sense that I think we should ban encryption or backdoor it because those are both stupid non-solutions. But it is a legitimate problem that law enforcement faces that has no good solution.