Hashing Passwords over Finite Fields (gardhr.github.io)

I know the readme says not vulnerable to length extension, but couldn't you create a collision between

M, and E(M)?

Took a quick look at the source, seems it would be possible because E(M) is just M joined with 1e until it's bigger than O(max(A, B, C))

But i may have oversimplified your extension function