This is a C program that implements it: http://131002.net/quark/
This is a Linux program, so the free d/l Notepad light is good to view it, not Windows notepad (where the lines are horribly goofy. WinRAR, etc., will decompress, as will Linux distro's. (it's a tar.gz file.)
I haven't run into this one before, but it's a lightweight and fast hash block cipher. RFID apparently is a good use for it.