3 ms·
Random padding increases the number of requests necessary by a couple orders of magnitude. It would be easy enough to filter out the noise if you tried each gue
by JshWright 13y ago
Random padding increases the number of requests necessary by a couple orders of magnitude. It would be easy enough to filter out the noise if you tried each guess enough times.
It would certainly increase the number of requests necessary to a quantity that (for the vast majority of cases) would be well above any sane usage, and couple easily be rate limited.
Credit where it's due, StavrosK and I were discussing this earlier, and averaging out the noise was his idea.
- peterwwillis 13y agoYeah, the important part is to randomize the output itself, in addition to padding. Even without the padding it makes for a significant challenge to determine just where your known plaintext is to compare from. But with enough attempts, if deflate eventually succeeds in shortening a message on a successful match, you could eventually find the matching message. Like you say, probably too long to be effective (depending on the number of random permutations and the size of the secret)
- phlo 13y agoWhat about deterministic padding? As a (badly thought through) example: Hash the plaintext, then use the first couple of bits of that result as your padding size. This should counteract averaging of requests. On the other hand, an attacker might work around this by adding a unique token in addition to their guess...