It is said that FC5 was leaked three days earlier than the official release. It is bittorrented also. Keep in mind that this might be a hoax. I’m pretty much sure you know that MD5 can be easily faked and that GnuPG has been broken a few days ago. So, this might be no go. (But who in the world will make such a fake for nothing?)
Anyway, to download or not; it’s up to you.