Geosecurity methods and devices using geotags derived from noisy location data from multiple sources

• US 8,315,389 B2
• Filed: 01/25/2010
• Issued: 11/20/2012
• Est. Priority Date: 01/25/2010
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Qiu, Di, Lo, Sherman, De Lorenzo, David S., Boneh, Dan, Enge, Per
• Primary Examiner(s): Shaw, Yin-Chen
• Assistant Examiner(s): WANG, HARRIS C
• Application Number:
  US12/657,677
• Publication Number:
  US 20110181470A1
• Time in Patent Office: 1,030 Days
• Field of Search: 380/258
• US Class Current: 380/258
• CPC Class Codes: G01S 5/02523 Details of interaction of receiver with radio-map
• CPC Class Codes: G08B 21/0213 System disabling if a separation threshold is exceeded disabling electrical appliances in case of unplugging G08B13/1409
• CPC Class Codes: G08B 21/0269 System arrangements wherein the object is to detect the exact location of child or item using a navigation satellite system, e.g. GPS
• CPC Class Codes: G08B 21/0283 via a telephone network, e.g. cellular GSM
• CPC Class Codes: H04L 63/107 wherein the security policies are location-dependent, e.g. entities privileges depend on current location or allowing specific operations only from locally connected terminals
• CPC Class Codes: H04W 12/08 Access security
• CPC Class Codes: H04W 4/02 Services making use of location information

Abstract

In a geo-security system, a device receives RF signals from multiple distinct classes of RF communication systems and extracts location-dependent signal parameters. A current geotag is computed from the parameters by fuzzy extractors involving quantization of the parameters and Reed-Solomon decoding to provide a reproducible unique geotag. The current geotag is compared with a stored geotag, and a geo-secured function of the device is executed based on the result of the comparison. The use of multiple signal sources of different types, combined with special fuzzy extractors provides a robust geotag that allows both lower false rejection rate and lower false acceptance rate.

Claims

1. A method for geo-security comprising:

receiving at a device RF communication signals transmitted from N multiple distinct classes of RF communication systems;

extracting at the device from the RF communication signals N signal parameters x′

that are time-invariant and location-dependent;

computing at the device a current geotag T from the signal parameters x′ and

a public identifier P associated with a geo-secured function of the device;

comparing at the device the current geotag T′

with a stored geotag T;

and

executing at the device the geo-secured function based on the result of the comparison of the current geotag T′

with the stored geotag T;

wherein computing the geotag from the signal parameters comprises;

quantizing the N signal parameters x′

to produce N corresponding quantized signal parameters q′

;

computing a vector c′

from q′ and

P; and

computing the geotag T from c′

using Reed-Solomon decoding and a hash function.

2. The method of claim 1 further comprising cryptographically authenticating at least one of the RF communication signals.

3. The method of claim 1 wherein executing the geo-secured function based on the result of the comparison of the current geotag T′

with the stored geotag T comprises executing the geo-secured function if the current geotag T′

matches the stored geotag T.

4. The method of claim 1 wherein executing the geo-secured function based on the result of the comparison of the current geotag T′

with the stored geotag T comprises executing the geo-secured function if the current geotag T′

does not match the stored geotag T.

5. The method of claim 1 wherein each of the N multiple distinct classes of RF communication systems is a class selected from the group consisting of cellular communications, television communications, radio communications, terrestrial navigational, satellite navigational, satellite communication, wireless internet, bluetooth, and active RF identification.

6. The method of claim 1 wherein each of the N signal parameters x′

comprises a signal parameter selected from the group consisting of time of arrival (TOA), time difference of arrival (TDOA), direction of arrival (DOA), angle of arrival (AOA), signal strength (SS), received signal strength (RSS), signal-to-noise ratio (SNR), bit error rate (BER), envelope to cycle difference (ECD) and code carrier divergence (CCD).

7. The method of claim 1 wherein the geo-secured function is a function selected from the group consisting of decrypting data stored on the device, enabling an audible ringer, and transmitting an alarm signal.

8. The method of claim 1 wherein 4≦

N≦

6.