"Time leaks are not fundamental to computing. They can be fundamental to running concurrent adversarial processes on the same core, though." Wrong. Even if yo

"Time leaks are not fundamental to computing. They can be fundamental to running concurrent adversarial processes on the same core, though." Wrong. Even if you separate different privilege levels onto different physical computers, and they only exchange information by message passing, then they are likely to leak information merely from the message timing. The message timing may indicate what has been cached or pre-computed on the privileged machine. So it's a matter of sending messages from the malicious machine such that they manipulate what is cached/pre-computed on the privileged machine based on the contents of privileged information. Manipulating what is cached/pre-computed is generally not too hard for an attacker; the real trick is doing so based on the contents of privileged information. But it's conceivable that you could extract some information from a database by determining which pages of a btree got cached when you try (and fail) to look at something you're not supposed to. It might be hard to extract the 1000th byte of a big text field that way, but you might be able to find out whether "joe" or "sally" is the person you're looking for. Sounds a bit difficult in practice, but computing (perhaps more than any other field) tends to quickly eliminate the difference between theory and practice when the motivation is strong enough.