[jerf]

Copyright already de facto works that way; you get copyright the moment it is fixed in the relevant medium, there is no publication or public release requirement. Patents have their own complicated things, but part of the definition of a patent is that it is for public release, so "secret patent" is theoretically a contradiction. (As my phrasing suggests I have little long-term confidence in our systems maintaining that truth, but I believe it is true right now.)

[greensoap]

There are secret patents in the realm of national defense (think nuclear). The patent doesn't issue until the secrecy order is rescinded and the term begins once issued; IIRC.

[hkmurakami]

> "secret patent" is theoretically a contradiction

There are "submarine patent" strategies though, which seek to postpone revelation of a patent for as long as possible.

[monochromatic]

Less of a problem these days though, since patent term is now measured from priority date (whereas it used to be measured from issue date).