Cool! This reminds me a lot of this[0] where there was a specification for a custom VM in a newspaper along with a binary. It still blows me away when I read how they solved the puzzle.
> I imagine that this would be a good way to find some of the best reverse-engineers in the world :)
Just a consideration: aren't the names of these persons "principally" known (at least if you are willing to do some investigations) if you are a company/government agency that has an interest in them?
Nope. How would you find out who reverse engineers a lot and gets good at it?
Some names will be popular through fame or common channels, but you'll never get a full list. Especially RE when some of their activities aren't legal and they don't want to be found.
I'd imagine that this is a good way to pique their interest. Then, when they succeed with solving the puzzle, they are less likely to forego the "prize" of working with the agency.
I (and I know quite some programmers who think the same) really hate it when for piquing my interest some fancy puzzle/problem is presented, but the real work that is to be done has nothing to do with the marketing. I don't believe that such kind of "false advertising" is a smart way to retain talent.
If I wanted to attract talent, I would rather put some problems on the company website that are really related to problems that occur(ed) in such a job position to attract talent that exactly loves the kind of problems that likely does occur at the job position that I want to fill.