User authentication systems and methods

1. A method comprising:

detecting, by a user authentication system, a touch input on a lock screen of a mobile device while the lock screen displays a notification of an incoming voice call;

determining, by the user authentication system, a movement of the touch input across the lock screen;

determining, by the user authentication system based on the determining of the movement, that the touch input satisfies an end-user-defined authentication key requirement that includes an end-user-defined setting specifying that a direction of a vector of the touch input across the lock screen and an angle tolerance requirement of a selected number of degrees of the vector will not be considered as part of the end-user-defined authentication key requirement; and

facilitating, by the user authentication system based on the determining that the touch input satisfies the end-user-defined authentication key requirement, a pick-up of the incoming voice call, wherein, based on the end-user-defined setting, the determining that the touch input satisfies the end-user-defined authentication key requirement is performed irrespective of a direction in which the touch input is directed across the lock screen.

2. The method of claim 1 , wherein:

the end-user-defined authentication key requirement comprises an end-user-defined distance requirement; and

the determining that the touch input satisfies the end-user-defined authentication key requirement includes determining that a distance of movement of the touch input across the lock screen satisfies the end-user-defined distance requirement.

3. The method of claim 2 , wherein:

the end-user-defined authentication key requirement comprises an end-user-defined tolerance for the end-user-defined distance requirement; and

the determining that the distance of movement of the touch input across the lock screen satisfies the end-user-defined distance requirement includes determining that the distance of movement of the touch input across the lock screen satisfies the end-user-defined distance requirement within the end-user-defined tolerance for the end-user-defined distance requirement.

4. The method of claim 1 , wherein:

the end-user-defined authentication key requirement comprises an end-user-defined vector number requirement; and

the determining that the touch input satisfies the end-user-defined authentication key requirement includes determining that a number of vectors representative of the touch input across the lock screen satisfies the end-user-defined vector number requirement.

5. The method of claim 1 , further comprising providing, by the user authentication system for display on the lock screen of the mobile device, a distance indicator that indicates, in real time, a current distance of movement of the touch input as the touch input moves across the lock screen.

6. The method of claim 1 , further comprising:

providing, by the user authentication system for display on a touch screen of the mobile device, a settings screen that prompts an end user of the mobile device to define an authentication key;

detecting, by the user authentication system, an authentication-key-defining touch input across the settings screen;

determining, by the user authentication system based on the authentication-key-defining touch input, one or more attributes of the authentication-key-defining touch input across the settings screen; and

defining, by the user authentication system based on the one or more attributes of the authentication-key-defining touch input, the authentication key.

7. The method of claim 6 , further comprising:

providing, by the user authentication system for display on the touch screen of the mobile device, an additional settings screen that includes an option to define the end-user-defined setting to specify that the direction of the vector representative of the touch input across the lock screen will not be considered as part of the end-user-defined authentication key requirement.

8. The method of claim 6 , further comprising:

providing, by the user authentication system for display on the touch screen of the mobile device, an additional settings screen that includes one or more options to modify the authentication key, the one or more options comprising at least one of an option to modify a distance threshold specified by the authentication key and an option to define an end-user-defined tolerance of the distance threshold specified by the authentication key.

9. The method of claim 1 , embodied as computer-executable instructions on at least one non-transitory computer-readable medium.

10. A method comprising:

detecting, by a user authentication system while a lock screen is displayed on a touch screen of a mobile device, a touch input across the lock screen of the mobile device;

determining, by the user authentication system, a movement of the touch input across the lock screen;

determining, by the user authentication system based on the determining of the movement, that the touch input satisfies an end-user-defined authentication key requirement that includes an end-user-defined setting specifying that a direction of the touch input across the lock screen and an angle tolerance requirement of a selected number of degrees of the vector will not be considered as part of the end-user-defined authentication key requirement; and

facilitating, by the user authentication system based on the determining that the touch input satisfies the end-user-defined authentication key requirement, access to a feature of the mobile device, wherein, based on the end-user-defined setting, the determining that the touch input satisfies the end-user-defined authentication key requirement is performed irrespective of a direction in which the touch input is directed across the lock screen.

11. The method of claim 10 , wherein:

the detecting of the touch input across the lock screen of the mobile device is performed while the lock screen displays a notification of an incoming voice call; and

the facilitating of the access to the feature of the mobile device comprises facilitating a pick-up of the incoming voice call.

12. The method of claim 10 , embodied as computer-executable instructions on at least one non-transitory computer-readable medium.

13. A system comprising:

at least one physical computing device that:

detects a touch input on a lock screen of a mobile device while the lock screen displays a notification of an incoming voice call;

determines a movement of the touch input across the lock screen;

determines based on the determination of the movement that the touch input satisfies an end-user-defined authentication key requirement that includes an end-user-defined setting specifying that a direction of a vector representative of the touch input across the lock screen and an angle tolerance requirement of a selected number of degrees of the vector will not be considered as part of the end-user-defined authentication key requirement; and

facilitates, after the at least one physical computing device determines that the touch input satisfies the end-user-defined authentication key requirement, a pick-up of the incoming voice call, wherein, based on the end-user-defined setting, the at least one physical computing device determines that the touch input satisfies the end-user-defined authentication key requirement irrespective of a direction in which the touch input is directed across the lock screen.

14. The system of claim 13 , wherein:

the end-user-defined authentication key requirement comprises an end-user-defined distance requirement; and

the determining that the touch input satisfies the end-user-defined authentication key requirement includes determining that a distance of movement of the touch input across the lock screen satisfies the end-user-defined distance requirement.

15. The system of claim 14 , wherein:

the end-user-defined authentication key requirement comprises an end-user-defined tolerance for the end-user-defined distance requirement; and

the determining that the distance of movement of the touch input across the lock screen satisfies the end-user-defined distance requirement includes determining that the distance of movement of the touch input across the lock screen satisfies the end-user-defined distance requirement within the end-user-defined tolerance for the end-user-defined distance requirement.

16. The system of claim 13 , wherein:

the end-user-defined authentication key requirement comprises an end-user-defined vector number requirement; and

the determining that the touch input satisfies the end-user-defined authentication key requirement includes determining that a number of vectors representative of the touch input across the lock screen satisfies the end-user-defined vector number requirement.

17. The system of claim 13 , wherein the at least one physical computing device provides, for display on the lock screen of the mobile device, a distance indicator that indicates, in real time, a current distance of movement of the touch input as the touch input moves across the lock screen.

18. The system of claim 13 , wherein the at least one physical computing device:

provides, for display on a touch screen of the mobile device, a settings screen that prompts an end user of the mobile device to define an authentication key;

detects an authentication-key-defining touch input across the settings screen;

determines, based on the authentication-key-defining touch input, one or more attributes of the authentication-key-defining touch input across the settings screen; and

defines, based on the one or more attributes of the authentication-key-defining touch input, the authentication key.

19. The system of claim 18 , wherein the at least one physical computing device provides, for display on the touch screen of the mobile device, an additional settings screen that includes an option to define the end-user-defined setting to specify that the direction of the vector representative of the touch input across the lock screen will not be considered as part of the end-user-defined authentication key requirement.

20. The system of claim 18 , wherein the at least one physical computing device provides, for display on the touch screen of the mobile device, an additional settings screen that includes one or more options to modify the authentication key, the one or more options comprising at least one of an option to modify a distance threshold specified by the authentication key and an option to define an end-user-defined tolerance of the distance threshold specified by the authentication key.