What are the legal implications of this? As far as I understood reverse engineering using disassembled code isn't legal. And this isn't just reading the disassembled code - they're taking it wholesale.
Now redistributing that code might maybe possibly get you into hot water, but to find out you'll need to go through a trial. So you use your disassembled source to learn the algorithm, then reimplement it in your own style. Now you're not even in the gray with respect to the original source.