Implementations of data security technologies are disclosed. In an implementation, a plurality of feature points of a user-selected image are determined. A first plurality of interactive operations performed on at least a portion of the plurality of feature points by a user are detected during lock screen passcode set up of a mobile computing device. The first plurality of interactive operations are stored. The user-selected image is displayed on a lock screen when the mobile computing device is in a locked state. A second plurality of interactive operations on a touchscreen of the mobile computing device are detected when the mobile computing device is in the locked state, and the mobile computing device is unlocked if the second plurality of interactive operations match the first plurality of interactive operations.