patent secrecy orders
Interesting. The Federal government can essentially make a patent a classified document. At the end of fiscal year 2013, 5,445 such orders were in effect. The majority seem to have some link with the government (perhaps sponsored by a grant?), but 21 "John Doe" orders are included, issued with regard to a private patentee whose name is kept secret. Here's more on the Invention Secrecy Act.