Challenge generation for verifying users of computing devices
Challenging a current user of a computing device by measuring characteristics of user actions sensed by a computing device, determining that the measurements meet a uniqueness condition with respect to corresponding measurements in a comparison set of actions, recording the user actions and their measurements in a set of challenge actions associated with an authorized user, and responsive to a challenge requirement to determine whether a current user of the computing device is the authorized user, selecting challenge actions associated with an authorized user, prompting the current user to perform the selected challenge actions that are then sensed by the computing device, measuring characteristics of the prompted actions, and determining that the measurements of the characteristics of the prompted actions meet a similarity condition with respect to measurements of corresponding characteristics of the selected challenge actions.
1. A method for challenging a user of a computing device, the method comprising:
measuring one or more characteristics of a user action sensed by a computing device and performed by an authorized user of the computing device subsequent to the authorized user of the computing device having been identified as the authorized user of the computing device;
determining that the measurements of the characteristics of the user action performed by the authorized user of the computing device subsequent to the authorized user of the computing device having been identified as the authorized user of the computing device meet a uniqueness condition with respect to measurements of corresponding characteristics of a corresponding action in a comparison set of actions;
recording the user action and the measurements of the characteristics in a set of challenge actions associated with an authorized user;
performing the measuring, determining, and recording for a plurality of different user actions associated with the authorized user responsive to determining that the measurements of the characteristics meet the uniqueness condition; and
responsive to a challenge requirement to determine whether a current user of the computing device is the authorized user,
selecting one or more of the challenge actions associated with the authorized user,
prompting the current user of the computing device to perform the selected challenge actions, wherein the prompted actions performed by the current user are sensed by the computing device,
measuring one or more characteristics of the prompted actions performed by the current user, and
determining that the measurements of the characteristics of the prompted actions performed by the current user meet a similarity condition with respect to measurements of corresponding characteristics of the selected challenge actions,
wherein the measuring, determining, recording, performing, selecting, and prompting are implemented in any of
(a) computer hardware, and
(b) computer software embodied in a non-transitory, computer-readable medium.
2. The method according to claim 1 wherein the selecting, prompting, measuring, and determining that are performed responsive to the challenge requirement are performed responsive to a failed attempt to determine whether the current user is the authorized user.
3. The method according to claim 1 wherein the measuring comprises measuring characteristics of the user actions that are in the form of two-dimensional geometric patterns that are input via a touch screen of the computing device when using an on-screen keyboard of the computing device.
4. The method according to claim 1 wherein the measuring comprises measuring characteristics of the user actions that are in the form of two-dimensional geometric patterns that are input via a touch screen of the computing device when tracing a pattern among graphic elements of a displayed set of graphic elements.
5. The method according to claim 1 wherein the measuring comprises measuring characteristics of the user actions that are in the form of three-dimensional input patterns that combine two-dimensional geometric input patterns with a spatial orientation of the computing device at input time of the two-dimensional geometric input patterns.
6. The method according to claim 1 wherein the determining that the measurements of the characteristics meet the uniqueness condition comprises determining wherein the comparison set of actions includes actions and characteristic measurements associated with a reference set of users of other computing devices.
7. The method according to claim 1 wherein the selecting and prompting are performed when an attempt is made by the current user of the computing device to access any of (a) a software application hosted by the computing device and (b) an operating system function of the computing device that are configured to trigger the challenge requirement responsive to the attempt.
8. The method according to claim 1 wherein the selecting and prompting are performed when the measurements of the characteristics of one of the user actions that are detected at different times differ by more than a predefined acceptable variance.