Thanks for pointing that out - I kinda missed it until seeing your post. I went through each step - it's still a bit convoluted, but definitely helps me appreciate hashing functions. It's probably very easy for a poorly coded hash function to accidentally wipe important data or accidentally and a bunch of data with zeroes, so it's pretty cool to see a lot of ROT and XOR usage which does more interesting things with the original data.

Had no idea about the prime roots and multiplication, that's pretty clever too.