Beware unrealistic hypotheticals. (Say, what's the cost to build such a safe?)
Short of dismissing the question out of hand, the point remains that it is still a mere matter of money - something which can be soaked out of taxpayers as needed. Even if we're talking a small jurisdiction with grossly insufficient funds, I'll meet your hypothetical with one where the US Military is invited to have a whack at it - and they can whack pretty hard. It's just a matter of money, and for all practical purposes through history that's been enough to crack any safe. ...and with that kind of money in that safe, I'm sure you could resolve the problem. Short of a scenario where forcing the safe would provably destroy evidence, or delays cause grave bodily harm, they can put the safe in the evidence warehouse and indefinitely assign someone to resolve the issue, while you cool your heels in Graybar Hotel until they open it or you save taxpayers the cost of doing so.
This in contrast to encryption, where any idiot can pick a good algorithm with a high-bitcount high-entropy key which could not be cracked using the resources of the universe. This isn't a hypothetical, this is the OP case. Here, the prosecution truly does hinge on the defendant incriminating himself: no cooperation = no conviction.
If you can prove a safe, like encryption, can't be cracked short of universe-scale efforts, I'll change my position.
Short of dismissing the question out of hand, the point remains that it is still a mere matter of money - something which can be soaked out of taxpayers as needed. Even if we're talking a small jurisdiction with grossly insufficient funds, I'll meet your hypothetical with one where the US Military is invited to have a whack at it - and they can whack pretty hard. It's just a matter of money, and for all practical purposes through history that's been enough to crack any safe. ...and with that kind of money in that safe, I'm sure you could resolve the problem. Short of a scenario where forcing the safe would provably destroy evidence, or delays cause grave bodily harm, they can put the safe in the evidence warehouse and indefinitely assign someone to resolve the issue, while you cool your heels in Graybar Hotel until they open it or you save taxpayers the cost of doing so.
This in contrast to encryption, where any idiot can pick a good algorithm with a high-bitcount high-entropy key which could not be cracked using the resources of the universe. This isn't a hypothetical, this is the OP case. Here, the prosecution truly does hinge on the defendant incriminating himself: no cooperation = no conviction.
If you can prove a safe, like encryption, can't be cracked short of universe-scale efforts, I'll change my position.