4 ms·
> the problem arises when AMD64 takes 9 + k cycles for k bytes of input while cryptographic engineers have tested on IA32e and assumed a constant overhead of 7
by Gordonjcp 4y ago
> the problem arises when AMD64 takes 9 + k cycles for k bytes of input while cryptographic engineers have tested on IA32e and assumed a constant overhead of 7 cycles.
Why is that a problem? Doesn't that just leak something you could determine by just looking at the CPU type?
- bluGill 4y agoThat also leaks how many bytes of data are being processed. This sometimes matters. When checking for a password match you have to check all characters in the.string otherwise you leak where the mismatch was. Even in a properly salted and hashed scheme that makes breaking the password easier.
- jeroenhd 4y agoThese side channel attacks allow perfectly secure algorithms to leak plaintext or even complete keys.