3 ms·
What? Pretty sure you're wrong. Yes, MD5 preimage resistance is not broken (to a reasonable degree). If you have the Ubuntu 16.04 ISO (you do), and if you hav
by hatsunearu 11y ago
What? Pretty sure you're wrong.
Yes, MD5 preimage resistance is not broken (to a reasonable degree).
If you have the Ubuntu 16.04 ISO (you do), and if you have its hash, the attack to craft a different ISO with the same hash is a collision attack.
A preimage attack is if you had some hash y where y=H(x) where x is some file/whatever, and trying to find out possible values of u that give rise to y when you do H(u), without the knowledge of x.
- avar 11y agoNo. What you're describing is just a subset of preimage attacks. Not having knowledge of x is just one type of preimage attack, a "preimage resistance". You can also know x, then it's a "second-preimage resistance".[1] Which is not the same as a collision attack. Where you're trying to find x and y such that h(x) = h(y) without anyone specifying x or y in advance. By definition a collision attack is an attack where you specifically craft both x and y such that they exploit weaknesses in the algorithm. It's not enough to know an arbitrary x or y that someone else has made, because that value isn't going to be exploiting the weakness. 1. https://en.wikipedia.org/wiki/Preimage_attack https://en.wikipedia.org/wiki/Preimage_attack
- hatsunearu 11y agoyeah, you're right. my bad.
- mceachen 11y ago(how many sites on the internet have a discussion where people are both patient and civil with each other, and the discussion results in mutual understanding?)
- hatsunearu 11y agoHmm, I personally haven't seen action in discussion where this kinda stuff doesn't happen; maybe I just pick the comments I reply well.