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Geoencryption Using Loran

Geoencryption Using Loran. Di Qiu, Sherman Lo, Per Enge Stanford University. Sponsored by FAA Loran Program. Why Geoencryption?. Unsecure world Data/Information security Piracy concern Traditional cryptosystems have inconveniences or weaknesses Something you know: PIN, passwords

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Geoencryption Using Loran

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  1. Geoencryption Using Loran Di Qiu, Sherman Lo, Per Enge Stanford University Sponsored by FAA Loran Program

  2. Why Geoencryption? 2007 Convention and Technical Symposium - ILA-36 Unsecure world • Data/Information security • Piracy concern Traditional cryptosystems have inconveniences or weaknesses • Something you know: PIN, passwords • Something you have: key, smart card • Something you are: biometrics

  3. Location for Security • Universality • Do all people have it? • Collectability • How well can an identifier be captured or quantified? • Circumvention • foolproof • Uniqueness • Can people be distinguished based on an identifier? 2007 Convention and Technical Symposium - ILA-36

  4. Encryption and Authentication Encryption Communication Channel --------------------------------------------------- @#)&)*+!#$N$&*&$&=W& /-!&)$#+ @#)&)*+!#$N$&*&$&=W& /-!&)$#+ --------------------------------------------------- Authentication Communication Channel --------------------------------------------------- --------------------------------------------------- --------------------------------------------------- --------------------------------------------------- Verify 2007 Convention and Technical Symposium - ILA-36

  5. Geoencryption --------------------------------------------------- @#)&)*+!#$N$&*&$&=W& /-!&)$#+ geotag Sender Receiver 2007 Convention and Technical Symposium - ILA-36

  6. Geodecryption Loran Receiver Feature Extraction @#)&)*+!#$N$&*&$&=W& /-!&)$#+ Verify yes --------------------------------------------------- 2007 Convention and Technical Symposium - ILA-36

  7. Why Loran? GPS Loran Stationary transmitters Low absolute accuracy, high repeatable accuracy Northern hemisphere High SNR Hard to jam and spoof Indoor capable Data channel (eLoran) • Non-stationary satellites • High absolute accuracy, high repeatable accuracy • Global coverage • Low SNR • Easy to jam and spoof • Indoor NOT capable • Data channel 2007 Convention and Technical Symposium - ILA-36

  8. Security Analysis Outline Security Loran Receiver Loran Receiver Feature Extraction Feature Extraction • Vulnerabilities of Protocol/Implementation • Spoof • Replay • “Parking Lot” Attack Tag Size IV. Spatial decorrelation Modify location parameters d Same tag? 2007 Convention and Technical Symposium - ILA-36

  9. m m m h h h K K K • Spoof • Replay • Parking lot • Spatial decorr. Signal Authentication ELR MAC h’ ?= h • TESLA – Timed Efficient Stream Loss-tolerant Authentication • Authenticating message = key (K) + tag (h) • Tag = MAC (Data, Key) 2007 Convention and Technical Symposium - ILA-36

  10. Spoof • Replay • Parking lot • Spatial decorr. Authentication Test 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 tag key • Middletown • Circular TESLA chain • 50% Bandwidth • Message subtypes • Type 1-4 (0001-0100): first 148 bits of the tag • Type 5 (0101): last 12 bits of tag, • Type 6-9 (0110-1001): first 148 bits of key • Type 10 (1010): last 12 bits of key 2007 Convention and Technical Symposium - ILA-36

  11. Spoof • Replay • Parking lot • Spatial decorr. Authentication Test Result 2007 Convention and Technical Symposium - ILA-36

  12. Spoof • Replay • Parking lot • Spatial decorr. Loran Certified Receiver Replay Modified Location Information Signal Authentication Module Geotag Generation Module Navigation Receiver Loran input Tamper Resistant Location Verification @#)&)*+!#$N$&*&$&=W& /-!&)$#+ Decryption File input Original file 2007 Convention and Technical Symposium - ILA-36

  13. Spoof • Replay • Parking lot • Spatial decorr. Parking Lot Attack • False Accept Rate (FAR): % of unauthorized persons accepted in error • False Reject Rate (FRR): % of authorized persons who are incorrectly denied acceptance • Trade off between FAR and FRR 2007 Convention and Technical Symposium - ILA-36

  14. Spoof • Replay • Parking lot • Spatial decorr. Data Collection 2007 Convention and Technical Symposium - ILA-36

  15. Spoof • Replay • Parking lot • Spatial decorr. FAR & FRR Estimation Experimental Analysis Analytic Analysis user attacker Grid interval size FAR FAR = Q(interval size, s, distance) Grid Size FRR FRR = Q(interval size, s) 2007 Convention and Technical Symposium - ILA-36

  16. Spoof • Replay • Parking lot • Spatial decorr. Receiver Operating Curve Grid Size Better Performance 2007 Convention and Technical Symposium - ILA-36

  17. Spoof • Replay • Parking lot • Spatial decorr. Spatial Decorrelation low high distance • High spatial decorrelation is preferred. • Evaluation functions • Distance measure • Error rates measure - FAR • Information measure - relative entropy D(p||q) • Dependence measure - correlation coefficient 2007 Convention and Technical Symposium - ILA-36

  18. Spoof • Replay • Parking lot • Spatial decorr. Test Locations 2007 Convention and Technical Symposium - ILA-36

  19. Spoof • Replay • Parking lot • Spatial decorr. False Accept Rate- Different Stations High SNR results in high spatial decorrelation. 2007 Convention and Technical Symposium - ILA-36

  20. Spoof • Replay • Parking lot • Spatial decorr. Decorrelation DistanceFAR < 0.01 e-0.2445d Decorrelation distance is 18 meters for Middletown. 2007 Convention and Technical Symposium - ILA-36

  21. Spoof • Replay • Parking lot • Spatial decorr. False Accept Rate- Different Location Parameters TDOA/TOA > ECD > SNR 2007 Convention and Technical Symposium - ILA-36

  22. Spoof • Replay • Parking lot • Spatial decorr. Geotag Size 811 km 25.8 bits 2007 Convention and Technical Symposium - ILA-36 • Information measure • Entropy • Key/Geotag size • Station coverage • Information density • Spatial decorrelation

  23. Conclusion • Defeated vulnerabilities of geoencryption protocol and implementation • Signal authentication & certified receiver • Spatial decorrelation of Loran location parameters • Geotag size from Middletown is 26 bits • At least 226 trials of different locations to break it • How to increase geotag size? • Look into more parameters • Fuzzy extractor 2007 Convention and Technical Symposium - ILA-36

  24. Acknowledgement The authors would like to thank Ben Peterson, Kirk Montgomery, Jim Shima and USCG for their help during the research. 2007 Convention and Technical Symposium - ILA-36

  25. Backup Slides 2007 Convention and Technical Symposium - ILA-36

  26. Spoof • Replay • Parking lot • Spatial decorr. Demodulation Performance 2007 Convention and Technical Symposium - ILA-36

  27. Spoof • Replay • Parking lot • Spatial decorr. Message Loss 2007 Convention and Technical Symposium - ILA-36

  28. Spoof • Replay • Parking lot • Spatial decorr. Authentication Performance Data TESLA Segment Authentication (320 bits) 320/37  9 Loran messages 50% BW  18 Loran messages Authentication probability is proportional to SNR & BW. SNR Bandwidth 2007 Convention and Technical Symposium - ILA-36

  29. Spoof • Replay • Parking lot • Spatial decorr. TDOA Data 2007 Convention and Technical Symposium - ILA-36

  30. Distribution of Quantized TDOA- Grid Size 20m, Station George 2007 Convention and Technical Symposium - ILA-36

  31. PDF 2007 Convention and Technical Symposium - ILA-36

  32. Receiver Operating Curve Grid Size Better Performance 2007 Convention and Technical Symposium - ILA-36

  33. Spoof • Replay • Parking lot • Spatial decorr. TDOA Measurements 2007 Convention and Technical Symposium - ILA-36

  34. Decorrelation Distances- Different Parameters 2007 Convention and Technical Symposium - ILA-36

  35. Relative Entropies 2007 Convention and Technical Symposium - ILA-36

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