arkworks-rs
Pedersen CRH and Commitment always fails
There's a check that's done in the constraints impl of Pedersen CRH and commitment that appears here and here. It asserts that padded_input.len() * 8 == W::WINDOW_SIZE * W::NUM_WINDOWS.
In most windows, however, this check fails and the program panics. The problem is that you cannot always pad bytes to a specific bitlength. In particular, if W::WINDOW_SIZE * W::NUM_WINDOWS is not divisible by 8, then Pedersen computations are guaranteed to fail every time.
This isn't a PR bc I'm not sure the best way to fix this. Currently my hacky workaround is to just pick NUM_WINDOWS = 8, but that makes things multiple times slower in the benchmarks for my current project.
Actually here's a simple solution: rather than padding the input bytes, pad the input bits. The bits conversion is done anyway in both instances, so this is 0 overhead. I can make a PR for this