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No, not "pretty much anything". Proper encryption code needs to be written so that the timing and power consumption does not depend on the data, to avoid these
by not2b 5y ago
No, not "pretty much anything". Proper encryption code needs to be written so that the timing and power consumption does not depend on the data, to avoid these kinds of side channel attack. That usually means no conditional branches, so the same processor operations occur regardless of the ciphertext or the key.
- rocqua 5y agoWhilst that is true, power side channel attacks are an interesting case. If they become relevant, then your attacker is really quite close to the device. In most scenarios, once the attacker is that close you are probably fucked anyway. There are exceptions of-course. Using in-memory encryption, ingress detection, etc you might be able to remain safe in these cases. Moreover an attacker might be able to do power-analysis without leaving a trace. Whereas pulling out the RAM-sticks after freezing them leaves more of a mark. However, few of the scenarios involving good reason to use homomorphic encryption really stand up to an attacker having physical access to the encrypting device. Most of these scenarios are about secure shared computation. Where the threat model revolves around 'what if my computational partner is evil', not 'what if Ethan Hunt breaks in'. Generally, if someone has access to the machine, they will have access to the raw data anyway.