Grostl is an algorithm invented by Praveen Gauravaram, Lars Knudsen, Krystian Matusiewicz, Florian Mendel, Christian Rechberger, Martin SchlÀffer, Soren S. Thomsen .
The digests (hashes generated by this algorithm) are 256 bits (32 Bytes) and 512 bits (64 Bytes) in length.
You can read more about it on this page.