US Patent 9958990 Authenticating with active stylus

In one embodiment, a stylus operable to communicate wirelessly with a device through a touch sensor of the device contains one or more computer-readable non-transitory storage media embodying logic that is operable when executed to access first data representing a recently occurred authentication event involving the stylus or the device. The logic is further operable to access second data representing a pre-defined authentication event. The logic is further operable to compare the first data with the second data to authenticate a user to the stylus or the device, a stylus to the user or the device, or a device to the user or the stylus.