If you can backup the data ahead of time then it doesn't matter if the process is destructive. So couldn't they (in theory) dump the flash memory, then extract the key from the processor and use it to decrypt the memory?
Obviously not practical for mass surveillance, but it would work to read one particular person's phone, which is the issue at hand.
> Obviously not practical for mass surveillance, but it would work to read one particular person's phone, which is the issue at hand.
Eh. I mean, yes, if the issue at hand were ACTUALLY read this one particular person's phone, that would probably be a valid avenue of attack.
But the actual issue at hand here is "establish precedent that you can use the All Writ's Act to get a judge to hand you an ex parte order that lets you walk in to a tech company and order them to build you (and, crucially, cryptographically sign) the tools you want so that you can get whatever data your heart desires".
Once that precedent is in place for this "just this one phone we swear" order, nothing's stopping them from walking into Apple or Google or whoever with an order to build and sign a custom OS version that, say, copies all data to an FBI server and push it as an OTA update to a target.
Once All Writs has been expanded to mean "you have to build us signed, custom versions of your software to get us data we want", all bets are off.
No, because the data you actually need isn't the ciphertext, it's the key, and the key is stored in hardware; the process of trying to recover it through imaging is what's destructive and risky. If you ruin the device trying to decap a chip, you don't get a second crack at the key, and the ciphertext is forever useless.
Obviously not practical for mass surveillance, but it would work to read one particular person's phone, which is the issue at hand.