Abstract: A method authenticates users. During user enrollment, a computing device records 3D gesture samples captured by a depth sensor as performed by a first user. Each recorded gesture sample includes a temporal sequence of locations for multiple specified body parts. The device computes an average gesture, and selects an error tolerance. These are stored as a gesture template for the first user. A second user performs a gesture for authentication. The depth sensor captures a 3D gesture from the second user, where the captured 3D gesture includes a temporal sequence of locations for the multiple body parts. The device computes the distance between the captured 3D gesture and the average gesture. When the distance is less than the error tolerance, the second user is authenticated as the first user, and the device grants access to some secured features. Otherwise, the second user is not authenticated.