I didn't read this very carefully, but why does 128 bits automatically make it a hash? That's also the block size for AES, and the length of the string "US Cyber Command".
If they expect it to be cracked (which they might, why put it there if you don't expect anyone to crack it) it could be something much simpler. I'd maybe start looking at some sort of substitution scheme or something similar.
If they expect it to be cracked (which they might, why put it there if you don't expect anyone to crack it) it could be something much simpler. I'd maybe start looking at some sort of substitution scheme or something similar.