hacker.org

possible?

I notice efe has solved this too now.

So why is this challenge seen as being so hard? For me it fell out naturally from some Vigenere-style analysis - there are a few repetitions at multiples of 3 characters, and if you do frequency analysis on every third character you quickly see that the third, sixth, etc characters are all in the first half of the alphabet.

I guess recognizing that the other characters are abbreviations for US states requires some general knowledge... but it is at least easy to spot that they, too, come from a restricted set of digraphs.

I actually spent ages trying to find some representation of all the counties (?) within a state via letters, i.e. TNA would be the first (A) county within Tennessee. It took a while to see that the third letters were counts into the state's name.

Without the 'US' hint, this one is really hard.
Of course there is the title, but still.