3 ms·
Can someone help me understand what the major distinction is between this accomplishment (SHAttered) and the same team's The SHAppening (2015)? It looks like t
by bobbyyankou 10y ago
Can someone help me understand what the major distinction is between this accomplishment (SHAttered) and the same team's The SHAppening (2015)?
It looks like the did the same thing or something similar in 2^57.5 SHA1 calculations back then versus 2^63 SHA1 calculations this time.
- hiddencost 10y agohttps://en.wikipedia.org/wiki/SHA-1#The_SHAppening https://en.wikipedia.org/wiki/SHA-1#The_SHAppening
- detaro 10y agoSHAppening was a freestart collision, this is a "full" one. This stack overflow answer looks like a good description of freestart collisions: https://crypto.stackexchange.com/questions/29695/what-is-a-freestart-collision https://crypto.stackexchange.com/questions/29695/what-is-a-f... My attempt at TL;DR: SHA-1 works on blocks, and each block is processed and it's data "mixed" with a previous intermediate result based on the previous blocks (Merkle-Damgård construction). A freestart collision only shows blocks and values for the intermediate results which lead to a collision. For a full collision you still have to figure out what sequence of blocks gets the intermediate results to the necessary values.
- bobbyyankou 10y agoAh, cool. I didn't notice the distinction between freestart and full. Thanks for that link; it was very helpful.