[detrites]

This is very cool, but I can't understand how 60khz is enough resolution to usefully discern what would be happening inside a CPU, etc, that's running way faster than that? (Disclaimer: I can't read the article as it says "browser not supported".)

EDIT - Answered here: https://news.ycombinator.com/item?id=36332352

[dfox]

The idea is that in typical assymetric cryptosystem you do some variant of bitwise exponentation of “large values” (ie. slow) and both the power envelope and timing is directly related to individual bit values of the private key. This trivially works for RSA and also anything involving integer-like groups and then even for “classic” ECC, things like 25519 are intentionally designed to mitigate this kind of side channel.