CLOAKING WITH FOOTPRINTS TO PROVIDE LOCATION PRIVACY PROTECTION IN LOCATION-BASED SERVICES

• US 20150007341A1
• Filed: 08/29/2014
• Published: 01/01/2015
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Original Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Inventors: Cai, Ying, Xu, Ge
• Granted Patent: US 9,239,935 B2
• Time in Patent Office: Days
• US Class Current: 726/26
• CPC Class Codes: G06F 21/6254 by anonymising data, e.g. decorrelating personal data from the owner's identification
• CPC Class Codes: G06F 2221/2111 Location-sensitive, e.g. geographical location, GPS
• CPC Class Codes: H04L 63/0421 Anonymous communication, i.e. the party's identifiers are hidden from the other party or parties, e.g. using an anonymizer
• CPC Class Codes: H04L 63/18 using different networks or channels, e.g. using out of band channels cryptographic mechanisms or cryptographic arrangements for key distribution involving distinctive intermediate devices or communication paths H04L9/0827; cryptographic mechanisms or cryptographic arrangements for authentication using a plurality of channels H04L9/3215
• CPC Class Codes: H04W 12/02 Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/029 Location-based management or tracking services

Abstract

A method for using a location-based service while preserving anonymity includes receiving a location associated with a mobile node, receiving an anonymity level associated with the mobile node, computing a region containing the location of the mobile node and a number of footprints based on the anonymity level, wherein each of the footprints from a different user, and providing the region to a location-based service to thereby preserve anonymity of the mobile node. A method also allow a mobile device or its user to specify the anonymity level by selecting a public region consistent with a user'"'"'s feelings towards desired privacy.

Claims

1. A method for using a location-based service while preserving anonymity by continuous cloaking using footprints, the method comprising:

determining a base trajectory associated with a device, the base trajectory comprising at least two points;

determining an anonymity level, K, associated with the device;

computing a K-anonymity trajectory using the base trajectory, the anonymity level, and a set of historical trajectories comprising footprints of other users to thereby cloak time-series location samples for the device;

providing the K-anonymity trajectory to a location-based service to thereby preserve anonymity of the device and provide location privacy protection for the device;

wherein computing the K-anonymity trajectory comprises cloaking the base trajectory with a set of K−

1 trajectories.

2. The method of claim 1 wherein the set of other trajectories is a set of K−

1 other user trajectories.

3. The method of claim 1 wherein the computing the K-anonymity trajectory comprises performing an exhaustive search to find the K-anonymity trajectory.

4. The method of claim 1 wherein the computing the K-anonymity trajectory comprises applying a heuristic solution to find the K-anonymity trajectory.

5. The method of claim 1 wherein the computing the K-anonymity trajectory comprises cloaking the base trajectory with one trajectory.

6. The method of claim 1 wherein the computing the K-anonymity trajectory comprises cloaking the base trajectory with a set of K−

1 trajectories.

7. The method of claim 1 wherein the computing the K-anonymity trajectory comprises selecting a small set of trajectories from a database for cloaking.

8. The method of claim 1 wherein the anonymity level, K, being determined based on a spatial region specified by a user of the device.

9. The method of claim 8 wherein the anonymity level, K, being determined by measuring popularity of the spatial region specified by the user of the device based on footprints collected from visitors to the spatial region, wherein the footprints include historical location samples.

11. The method of claim 1 wherein the step of determining anonymity level is determined based on a spatial regions specified the mobile device.

10. A method for providing location-based services while preserving anonymity by continuous cloaking using footprints, the method comprising:

(a) determining a base trajectory associated with a mobile device, the base trajectory comprising at least two points;

(b) determining anonymity level, K, associated with the mobile device;

(c) computing a K-anonymity trajectory using the base trajectory, the anonymity level, and a set of K−

1 other trajectories using a computing device, wherein the set of other trajectories includes historical trajectories comprising footprints from other mobile devices to thereby cloak time-series location samples for the mobile device; and

(d) providing the K-anonymity trajectory to a location-based service used by the mobile device to thereby preserve anonymity of the mobile device and provide location privacy protection for the mobile device.

12. The method of claim 10 wherein the anonymity level, K, being determined based on a spatial region specified by a user of the mobile node.

13. The method of claim 12 wherein the anonymity level, K, being determined by measuring popularity of the spatial region specified by the user of the mobile node based on footprints collected from visitors to the spatial region.