So Uniloc are suing Mojang for patent infringement.
Here's a copy of the complaint,
and here's the patent itself.
Having read through the patent document it seems to describe a method for authenticating with an external service by means of a hash of data generated on an external smart card, which is sent to an external server (either a licensing system on a given network or on the Internet) to authorize access to some piece of software for a given license period before it must be authorized again... except Minecraft does nothing like this to my knowledge. What they describe sounds a lot like a Blizzard Authenticator, though.
Apparently this isn't the first time Uniloc have sued, they've also sued Gameloft and a bunch of other companies. Poor patent system - such good intent, and yet you only ever hear of patents in the context of people suing for tangentially related stuff to try and make a buck.
Also, yes, they misspelled Minecraft in the complaint. "Mindcraft" sounds awesome, whatever it is.