2 ms·
For N large enough, there is no noise floor. In some cases, you could realistically be attacking a system for months or years to obtain a key.
by murbard2 12y ago
For N large enough, there is no noise floor. In some cases, you could realistically be attacking a system for months or years to obtain a key.
- homakov 12y agoIn theory it works like a charm, but did anyone actually attacked for months? Speaking of web apps, locally it can work fine but in reality the more people are requesting the server the longer it will take to process our request. Days turn into years, and you have no idea if you're on the wrong path.
- xyzzy123 12y agoThere is the threshold at which each measurement is giving you less information than brute-force. At that point, you can say "this is not vulnerable to a timing attack" even if a timing side-channel is present. The larger the search space, the more noise you would be willing to put up with.... EDIT: I'm not sure what you mean by N. If you mean N as the size of the search space rather than N as the number of requests, I agree with you!
- murbard2 12y agoYou actually do both. Each measurement induces a probability distribution over the space upon which you bruteforce. Also not that timing attacks are quadratic in the noise to signal ratio and linear in key length which bruteforce is exponential in keylengths. So that threshold is likely many orders of magnitude smaller than you imagine.