Mojang is facing an infringement lawsuit filed by Uniloc, which claims that its software patent for a "system and method for preventing unauthorized access to electronic data" is seeing unauthorized use in the Android version of Minecraft: Pocket Edition. Though in the suit, which you can read right here thanks to Notch, Uniloc actually refers to the Mojang game as "Mindcraft."
Notch first shared the news of this legal matter with his Twitter followers, later adding that he'll willingly "throw piles of money at making sure [Uniloc] don't get a cent." That attitude grows out of his belief that software patents are "plain evil," since "innovation within software is basically free" and "patents only slow it down." He later took to his Tumblr with a more detailed explanation of his stance on the issue, one which starts with a most excellent example scenario drawn from The Matrix.
Also, let's just make this doubly clear: Uniloc's lawsuit refers to Mojang's millions-selling, multi-platform game as Mindcraft. MINDCRAFT.
The software patent in question exists in the service of piracy protection. In this case, the Minecraft app for Android-powered smartphones and tablets communicates with a central server to perform a license check. That network check apparently falls under the umbrella of Uniloc's patent.
Mojang isn't the first to be targeted by the Luxembourg-based company. Uniloc took Electronic Arts to court over the Android version of Bejeweled 2, and also targeted Microsoft and Square Enix in similar software patent disputes (via Eurogamer).