While in need for a ZIP password cracking tool, I've found a nice open source program FCrackZip. It seems that it has been not yet ported to MorphOS, so I've tried and found it compiles out of a box. I've verified it works (on some real ZIP archives), then I've decided to put the port on MorphOS Files. Who knows, maybe someone will find it usable.

Thanks Krashan, this can be very useful.