Location verification

1. A location verifier comprising one or more computers having machine readable instructions, the location verifier being configured to:

receive a location report of a target mobile device, wherein the location report includes data characterizing a location for the target mobile device;

receive a list of mobile devices that are within a predefined proximity of the target mobile device;

interrogate each mobile device in the list of mobile devices for a list of detected devices, wherein each device in the list of detected devices is detected through radio frequency (RF) peer-to-peer communications; and

determine a likelihood that the location for the target mobile device has been spoofed based on the interrogating.

2. The location verifier of claim 1 , wherein the location verifier is further configured to search the list of mobile devices to identify a mobile device that is associated with the target mobile device.

3. The location verifier of claim 2 , wherein the association is based on a connection in social media.

4. The location verifier of claim 1 , wherein the location verifier is further configured to query a proximity evaluation service (PES) for the list of mobile devices.

5. The location verifier of claim 4 , wherein the PES is implemented as a passive location system.

6. The location verifier of claim 4 , wherein the PES is implemented as a home location register.

7. The location verifier of claim 4 , wherein the PES is implemented as a cellular broadcast system.

8. The location verifier of claim 1 , wherein each mobile device in the list of mobile devices is configured to detect the devices through Bluetooth protocol communications.

9. The location verifier of claim 1 , wherein each mobile device in the list of mobile devices is configured to detect the devices through WiFi protocol communications.

10. The location verifier of claim 1 , wherein each mobile device in the list of mobile devices is configured to detect the devices through communications made via the prefix routing over set elements (PROSE) protocol.

11. The location verifier of claim 1 , wherein the location verifier is configured to interrogate each of the mobile devices via a short message service (SMS) message.

12. The location verifier of claim 1 , wherein the location verifier is configured to interrogate each of the mobile devices via the mobile management entity (MME) protocol.

13. The location verifier of claim 1 , wherein the location verifier is configured to interrogate each of the mobile devices via the Session Initiation Protocol (SIP).

14. The location verifier of claim 1 , wherein the location verifier is configured to interrogate each of the mobile devices via the Hypertext Transfer Protocol (HTTP).

15. The location verifier of claim 1 , wherein the location verifier is configured to interrogate each of the mobile devices via the Transmission Control Protocol (TCP).

16. The location verifier of claim 1 , wherein the determining further comprises:

searching the list of mobile devices to identify a set of mobile devices that are associated with the target device; and

increasing the likelihood that the location for the target mobile device has been spoofed in response to determining that the set of mobile devices that are associated with the target device are the only mobile devices in the list of mobile devices that detect the target mobile device through RF peer-to-peer communication.

17. The location verifier of claim 1 , wherein the location verifier is further configured to:

determine a number of matches between a unique identifier of the target mobile device and unique identifiers included in each of the list of detected devices provided from each of the mobile devices that are within the predefined proximity of the target mobile device, wherein the likelihood that the location of the target mobile device has been spoofed is based on the determined number of matches.

18. A system comprising:

a memory configured to store machine readable instructions; and

a processing unit configured to access the memory and execute the machine readable instructions, the machine readable instructions comprising:

a target identifier configured to receive a location report from a target device that characterizes a location for the target device;

a proximity evaluation system (PES) interface configured to query a PES for a list of mobile devices that are within a predefined proximity of the location characterized in the location report;

a device interrogator configured to interrogate each mobile device in the list of mobile devices for other devices that are detected via a specified radio frequency (RF) based peer-to-peer protocol; and

a verification scorer configured to determine a confidence value for the location characterized in the location report based on the other devices detected by each interrogated mobile device, wherein the confidence value indicates a likelihood that the location for the target device has been spoofed.

19. The system of claim 18 , wherein the query includes data characterizing the specified RF based peer-to-peer communication protocol employed by each mobile device in the list of mobile devices.

20. A system comprising:

a memory configured to store machine readable instructions; and

a processing unit configured to access the memory and execute the machine readable instructions, the machine readable instructions comprising:

a target identifier configured to receive a location report from a target device that characterizes a location for the target device; and

a proximity evaluation system (PES) interface configured to query a PES for a list of mobile devices that are within a predefined proximity of the location characterized in the location report, wherein the query includes data specifying a peer-to-peer communication protocol employed by each mobile device in the list of mobile devices;

a device interrogator configured to interrogate each mobile device in the list of mobile devices for other devices that are detected via the specified peer-to-peer protocol;

wherein the target identifier is further configured to:

receive a list of other devices that are detected by the target device at the location characterized in the location report; and

determine a radio frequency (RF) fingerprint for the target device based on the location report provided from the target device and the list of other devices detected by the target device;

wherein the device interrogator is further configured to interrogate each mobile device in the list of mobile devices for a location report that characterizes a current location of a respective mobile device in the list mobile devices;

wherein the verification scorer is further configured to:

determine an RF fingerprint for each mobile device in the list of mobile devices based on the other devices that are detected at each respective mobile device and on the location report provided by each respective mobile device; and

compare the RF fingerprint of the target device to the RF fingerprint of each of the mobile devices in the list of mobile devices.

21. The system of claim 20 , wherein the confidence value determined by the verification scorer is also based on the comparison of the RF fingerprint for the target device to the RF fingerprint of each of the mobile devices in the list of mobile devices.

22. A method comprising:

querying, by a location verifier comprising one or more computing devices, a proximity evaluation system (PES) for a list of mobile devices that are within a predefined distance of a location characterized in a location report received from a target mobile device;

interrogating, by the location verifier, each of the mobile devices in the list of mobile devices for devices that are detected through a peer-to-peer communication protocol; and

determining, by the location verifier, a trustworthiness of the location characterized in the location report from the target mobile device based on the interrogating, wherein the trustworthiness corresponds to a likelihood that the location characterized in the location report provided from the target mobile device has been spoofed.

23. The method of claim 22 , wherein the determining further comprises searching the list of mobile devices for a mobile device that is associated with the target mobile device.