RCDA: Recoverable Concealed Data Aggregation for Data Integrity in Wireless Sensor Networks

1. RCDA: Recoverable Concealed Data Aggregation for Data Integrity in Wireless Sensor Networks Chien-Ming Chen, Yue-Hsun Lin, Ya-Ching Lin, Hung-Ming Sun IEEE Transactions on Parallel and Distributed Systems, Vol.23, No.4, April 2012 Presenter: 林顥桐 Date: 2012/11/19

2. Outline • Introduction • Encryption Scheme and Signature Scheme • RCDA Scheme for Homogeneous WSN • RCDA Scheme for Heterogeneous WSN • Implementation and Comparisons • Conclusion

3. Introduction • The usage of aggregation functions is constrained • The base station cannot verify the integrity and authenticity of each sensing data

4. Introduction • RCDA • The base station can verify the integrity and authenticity of all sensing data • The base station can perform any aggregation functions on them

5. Encryption Scheme and Signature Scheme • Encryption Scheme • Mykleton et al.’s Encryption Scheme • Signature Scheme • Boneh et al.’s Signature Scheme

6. Encryption Scheme and Signature Scheme • Mykleton et al.’s Encryption Scheme • Proposed a concealed data aggregation scheme based on the elliptic curve ELGamal(EC-EG) cryptosystem

7. Encryption Scheme and Signature Scheme • Boneh et al.’s Signature Scheme • Proposed an aggregate signature scheme which merges a set of distinct signatures into one aggregated signature • Based on bilinear map

8. Outline • Introduction • Encryption Scheme and Signature Scheme • RCDA Scheme for Homogeneous WSN • RCDA Scheme for Heterogeneous WSN • Implementation and Comparisons • Conclusion

9. RCDA Scheme for Homogeneous WSN

10. RCDA Scheme for Homogeneous WSN • Four procedures • Setup • Base Station(BS) generates the key pairs • Encrypt-Sign • Trigger while a sensor decides to send its sensing data to the cluster head(CH) • Aggregate • Launched after the CH has gathered all ciphertext-signature pairs • Verify • Receive the sum of ciphertext and signature from CH, BS can recover and verify each sensing data

11. RCDA Scheme for Homogeneous WSN • Setup • (PSNi, RSNi ): For each sensor SNi, the BS generates (PSNi,RSNi)by KeyGen procedure(Boneh scheme) where PSNi = vi and RSNi = xi • (PBS, RBS): These keys are generated by KeyGen procedure(Mykletun scheme) where PBS ={Y, E, p, G, n} and RBS = t Public key, where vi = xi*g Privacy key , randomly selected from Zp Y = t*G, E is an elliptic curve over a finite Fp, p is a prime number, G is a generator on E, n is the order of E, t is a privacy key randomly from Fp

12. RCDA Scheme for Homogeneous WSN • Setup • RSNi, PBS, H, are loaded to SNi for all i • BS keeps all public keys PSNi and its own RBS in privacy

13. RCDA Scheme for Homogeneous WSN • Encrypt-Sign Boneh’s signature Mykleton’s Encrypt

14. RCDA Scheme for Homogeneous WSN • Aggregate

15. RCDA Scheme for Homogeneous WSN • Verify • 1) • 2) • 3) • 4) ?

16. Outline • Introduction • Encryption Scheme and Signature Scheme • RCDA Scheme for Homogeneous WSN • RCDA Scheme for Heterogeneous WSN • Implementation and Comparisons • Conclusion

17. RCDA Scheme for Heterogeneous WSN

18. RCDA Scheme for Heterogeneous WSN • Five procedures • Setup • Necessary secrets are loaded to each H-Sensor and L-Sensor • Intracluster Encrypt • Involve when L-Sensor desire to send their sensing data to the corresponding H-Sensor • Intercluster Encrypt • Each H-Sensor aggregates the received data and then encrypts and signs the aggregated result • Aggregate • If an H-Sensor receives ciphertexts and signatures from other H-Sensor on its routing path, it activates the Aggregate procedure • Verify • Ensure the authenticity and integrity of each aggregated result

19. RCDA Scheme for Heterogeneous WSN • Setup • (RHi, PHi ): the BS generates this key pair for each H-Sensor according to KeyGen(Boneh’s scheme), i.e., RHi = xi and PHi= vi • (RBS, PBS): This key pair is generated by KeyGen(Mykletun’s scheme), i.e., PBS = {Y, E, p, G, n} and RBS = t Public key, where vi = xi*g Privacy key , randomly selected from Zp Y = t*G, E is an elliptic curve over a finite Fp, p is a prime number, G is a generator on E, n is the order of E, t is a privacy key randomly from Fp

20. RCDA Scheme for Heterogeneous WSN • Setup • The BS loads PBS to all L-Sensors. Each H-Sensor is loaded its own key pair (PHi, RHi), PBS, and several necessary aggregation functions • Each L-Sensor is required to share a pairwise key with its cluster head

21. RCDA Scheme for Heterogeneous WSN • Intracluster Encrypt • Ensure the establishment of a secure channel between L-Sensors and their H-Sensor

22. RCDA Scheme for Heterogeneous WSN • Intercluster Encrypt • After collecting all sensing data from all cluster members, an H-Sensor performs the prefered aggregation function on these data as its result

23. RCDA Scheme for Heterogeneous WSN • Intercluster Encrypt Boneh’s signature Mykleton’s Encrypt

24. RCDA Scheme for Heterogeneous WSN • Aggregate • If H3 receives (c1, ) from H1 and (c2, ) from H2, H3 will execute this procedure to aggregate (c1, ), (c2, ) and its own (c3, ) as follows: • Finally, H3 sends ( ) to H5.Similarly, H5 can also aggregate (c4, ), (c5, ), and ( ) then get a new aggregated result ( ) to the BS

25. RCDA Scheme for Heterogeneous WSN • Verify • 1) • 2) • 3) • 4) ?

26. Outline • Introduction • Encryption Scheme and Signature Scheme • RCDA Scheme for Homogeneous WSN • RCDA Scheme for Heterogeneous WSN • Implementation and Comparisons • Conclusion

27. Implementation and Comparisons • Implementation

28. Implementation and Comparisons • Comparisons • RCDA-HOMO has worst performance evaluation, because RCDA-HOMO provides better security

29. Conclusion • The base station can securely recover all sensing data rather than aggregated results • Integrate the aggregate signature scheme to ensure data authenticity and integrity in the design