Would the Intel SHA extensions help in creating SHA1 collisions? AMD Ryzen and EPYC supports them.
1 Answer
If you break the attack into two phases, like in the SHAttered paper, it may help the first phase. The researchers say that they used a CPU cluster for the first phase; the more expensive second phase used a GPU cluster.
...from an attacker’s point of view, it may seem best to implement the attack on a CPU in order to be able to claim a better attack complexity. However, a GPU being far more powerful, it is actually much more efficient to run it on the latter: the attack of [18] takes only a bit more than four days to run on a single GTX 970, which is much less than the estimated 150 days it would take using a single quad-core CPU.
The trade-off is that GPUs may be more difficult to program, but on the plus side, they are more cost-effective.