3 ms·
-> Can we throw exactly the same number of math (micro)operations into the spin loop? -> Can we just make sure the exact same operation operations occur?
by naniwaduni 7y ago
-> Can we throw exactly the same number of math (micro)operations into the spin loop?
-> Can we just make sure the exact same operation operations occur?
- kazinator 7y agoThe first idea seems way easier to achieve and maintain. It can be implemented at higher level around a complex, lumped operation, like calculating a signature, without having to go into all of that operation's subroutines to change everything to constant time. We could conceivably drop it into any language, wrapping it around any crypto, while treating that as a black-box.
- kazinator 7y agoCould also be faster. That is to say, variable-time calculations likely have a worst case time that is better than for the equivalent fixed-time calculations, since we just write the obvious code for the CPU using its normal instructions and optimize as usual. If we are able to box the padded time fairly tightly to the worst case, we are better off performance-wise than with the fixed-time implementations.