1. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 1© Nokia Solutions and Networks 2014 Privacy Preserving Log File Processing in Mobile Network Environment Shankar Lal 16-06-2015

2. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 2© Nokia Solutions and Networks 2014 Presentation outline Introduction and background review Cases of privacy breach Statistical analysis over Network trace Continuous fields anonymisation through Differential Privacy Discrete fields anonymisation through ℓ-diversity IP address anonymisation Future work and conclusion

3. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 3© Nokia Solutions and Networks 2014 Introduction and Objectives of this work

4. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 4© Nokia Solutions and Networks 2014 Background review Data Privacy Need of privacy in user data Tradeoff between data utility and data privacy

5. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 5© Nokia Solutions and Networks 2014 IP address as Personal Data Arguments on both sides EU consider it personal (UK is exception) US consider it non-personal

6. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 6© Nokia Solutions and Networks 2014 Privacy Laws PII (Personally Identifying Information) US privacy law Personal Data EU Data protection Directive

7. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 7© Nokia Solutions and Networks 2014 Cases of privacy breach from anonymised data sets

8. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 8© Nokia Solutions and Networks 2014 There's No Such Thing As An Anonymized Dataset

9. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 9© Nokia Solutions and Networks 2014 Netflix anonymous data set and user privacy breach

10. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 10© Nokia Solutions and Networks 2014 AOL anonymous data set of user queries

11. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 11© Nokia Solutions and Networks 2014 Identification of medical record of former governor of Massachusetts William Weld Former governor of Massachusetts

12. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 12© Nokia Solutions and Networks 2014 Statistical analysis over Network traces

13. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 13© Nokia Solutions and Networks 2014 Sample of a Network Log file

14. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 14© Nokia Solutions and Networks 2014 Statistical Analysis on network trace I

15. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 15© Nokia Solutions and Networks 2014 Statistical Analysis on network trace II Most used protocols Most used packet lengths Source and destination IP class count IP class packet length distribution

16. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 16© Nokia Solutions and Networks 2014 Functional dependencies between fields

17. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 17© Nokia Solutions and Networks 2014 Why packet length and timestamp fields are sensitive? Certain security incidents have fixed packet length Slammer worm 404 bytes Nachi worm 92 bytes Timestamp along with IP address reveals communication existed between parties.

18. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 18© Nokia Solutions and Networks 2014 Privatizing network trace

19. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 19© Nokia Solutions and Networks 2014 Privacy Enhancing Technologies (PETs) Hashing Encryption Randomization and Tokenization k-anonymity New Inclusions: Differential Privacy ℓ-diversity

20. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 20© Nokia Solutions and Networks 2014 k-anonymity Main idea: Generalization Suppression Perturbation

21. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 21© Nokia Solutions and Networks 2014 Example on network data set Sample Data set 2-anonymous data set

22. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 22© Nokia Solutions and Networks 2014 Differential Privacy: Anonymisation of continuous fields

23. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 23© Nokia Solutions and Networks 2014 Differential Privacy Differential privacy algorithm states that probability that data set D1 produces output C is very close to the probability of data set D2 producing same output. Laplace noise calculation: Scale parameter b = Δ f/ Mean μ =0 Δ f =sensitivity of the function = Privacy parameter Probability density plots of Laplace distributions

24. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 24© Nokia Solutions and Networks 2014 Noise addition through Differential Privacy Original Distribution =0.01 =0.1 Packet length field

25. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 25© Nokia Solutions and Networks 2014 Noise addition through Differential Privacy =0.01 =0.1 Original Distribution Timestamp field

26. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 26© Nokia Solutions and Networks 2014 Comparison between original and noisy data Packet Length Time stamp

27. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 27© Nokia Solutions and Networks 2014 ℓ-diversity: Anonymisation of discrete fields

28. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 28© Nokia Solutions and Networks 2014 ℓ-diversity A q-block is ℓ-diverse if contains at least ℓ “well-represented” values for the sensitive attribute (in other words, diversity in the sensitive attributes).

29. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 29© Nokia Solutions and Networks 2014 Example on network data set Sample Data set 3-diverse Data set

30. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 30© Nokia Solutions and Networks 2014 ℓ-diversity technique

31. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 31© Nokia Solutions and Networks 2014 Equivalence class creation Equivalence class name Protocol name Transport Protocols TCPUDP** Management Protocols DNSICMPDHCPARP Security Protocols TLSSSLSSHHTTPS Mobile Networks Protocols SSMPGTPGTPv2UCP Other Protocols ****

32. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 32© Nokia Solutions and Networks 2014 5-diverse data set

33. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 33© Nokia Solutions and Networks 2014 Other Noise addition techniques

34. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 34© Nokia Solutions and Networks 2014 Zero Mean noise addition

35. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 35© Nokia Solutions and Networks 2014 Noise addition by summing LSBs technique Example: 1414 1414+9= 1423 LSBs

36. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 36© Nokia Solutions and Networks 2014 IP address Anonymisation

37. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 37© Nokia Solutions and Networks 2014 Anonymising IP addresses Method: 1. Last octet Obfuscation Method: 2. Transformation to IP class Goal is to anonymise IP addresses but also preserve network topology information

38. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 38© Nokia Solutions and Networks 2014 Final Anonymised data set

39. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 39© Nokia Solutions and Networks 2014 Anonymised network trace

40. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 40© Nokia Solutions and Networks 2014 Conclusion and Future Work

41. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 41© Nokia Solutions and Networks 2014 Conclusion Preserving user privacy in a network trace. Analyzing Functional dependencies between the fields. Packet length and timestamp anonymisation by Differential Privacy and ℓ-diversity technique. Deciding the best values of privacy parameter ε IP addresses anonymisation by last octet obfuscation method.

42. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 42© Nokia Solutions and Networks 2014 Future work Framework for calculating best value of epsilon Re-identification testing Feature extraction/Clustering Anomaly detection/Malware Analysis

43. R 18 G 65 B 145 R 0 G 201 B 255 R 104 G 113 B 122 R 216 G 217 B 218 R 168 G 187 B 192 Core and background colors: 43© Nokia Solutions and Networks 2014 Thank you Questions?