Patent #6,857,067, apparently.
Patent trolling company Uniloc has filed a lawsuit against Minecraft developer Mojang, alleging that the Android version of Minecraft (referred to in the filing as Mindcraft) infringes patent #6,857,067.
Reported on Joystiq, patent #6,857,067 refers to a "system and method for preventing unauthorized access to electronic data" and the precise claim (107) references a "computer code executable on an electronic device to prevent unauthorized access to electronic data stored on the electronic device."
Uniloc is seeking payment for damages alongside ongoing royalties from Mojang.
"Unfortunately for them, they're suing us over a software patent," said Notch on his Twitter account. "If needed, I will throw piles of money at making sure they don't get a cent."
"Software patents are plain evil. Innovation within software is basically free, and it's growing incredibly rapid. Patents only slow it down."