I thought the researched decompiled the Skype client, posted the resulting source, reversed engineered the protocol, and wrote open source implementation. The d

I thought the researched decompiled the Skype client, posted the resulting source, reversed engineered the protocol, and wrote open source implementation. The decompiled source is definitely a derivative work and possibly copyrighted by Skype. It is hard to tell if the DMCA takedown is for that decompiled source. The other problem is that by looking at the decompiled source, his source is tainted. He will have a hard time showing that it isn't a derivative work. Especially if he wasn't really careful writing the source from scratch and not cleaning up the decompiled source.