How to remake Groestl hash function?

Question

Cryptography

There is a function, Grøstl, that gives a hash of 512 bits, how can I change it to give a hash of 256 bits?
It is not possible to cut off the first part of the 512b hash. It does not converge with 256...

Answer 1

I did not understand the algorithm, but everywhere it says that Grøstl is parameterized to the length of the result. Perhaps you just need to change (or pass) the l parameter in the implementation. Give the code or tell what you use.