If the work was classified and the people behind it were bound to secrecy, I would expect disclosure to be a one-shot affair: a big dump of documentation and code on WikiLeaks, say. That's not what happened. There was a paper, there was open source code, and Satoshi hanged around for years before disappearing. That would have been an insane level of exposure for somebody risking severe repercussions if caught leaking state secrets.