Yes, and in fact, for that (radio telescope data) case, there is a pretty obvious null 'key' you can hand over - or rather, load the data file into JodrellBank.

Yes, and in fact, for that (radio telescope data) case, there is a pretty obvious null 'key' you can hand over - or rather, load the data file into JodrellBank.exe and show them what it is. If, on the other hand, you have been trying to troll the police and MI5 with: % dd if=/dev/random of=terr0r_pl4nz.dat count=2048 Then, good luck with that. But really, stop doing that; it's not as clever as you think. In fact, the provocative filename gives reasonable suspicion you are an (incompetent) terrorist, and the police and security services don't like their time being wasted while you try and prove a point.