1. Chien-Ming Chen, Yue-Hsun Lin, Ya-Ching Lin, and Hung-Min Sun IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, VOL. 23, NO. 4, APRIL 2012 Citation:42 Presenter: 張哲豪 Date:2014/9/22

2.  Introduction  Preliminaries  RCDA-HOMO  RCDA-HETE  Analysis  Implementation  Comparisons  Conclusions 2

3.  To reduce the communication cost in WSN, data aggregation is performed by cluster head.  Problem ◦ Adversary has the ability to capture cluster heads. 3

4.  Concealed Data Aggregation ◦ data are encrypted during transmission ◦ cluster heads directly aggregate encrypted data without decryption (privacy homomorphism)  Problem ◦ The usage aggregation functions is constrained ◦ Base station can’t verify the integrity and authenticity of each sensing data. 4

5.  Recoverable Concealed Data Aggregation ◦ The base station can verify the integrity and authenticity of all sensing data. ◦ The base station can perform any aggregation functions on them. 5

6.  Introduction  Preliminaries  RCDA-HOMO  RCDA-HETE  Analysis  Implementation  Comparisons  Conclusions 6

7.  Homogeneous WSN ◦ cluster heads act as normal SNs.  Heterogeneous WSN ◦ cluster heads act as by powerful high-end sensors (H-Sensors) ◦ Different types of SNs 7

8.  Without compromising any SN or CH ◦ Forged messages with public information  Compromising SNs ◦ Obtain sensing data or forge malicious data  Compromising CHs ◦ Decrypt the ciphertext ◦ Forged aggregation results 8

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13.  Introduction  Preliminaries  RCDA-HOMO  RCDA-HETE  Analysis  Implementation  Comparisons  Conclusions 13

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17.  Introduction  Preliminaries  RCDA-HOMO  RCDA-HETE  Analysis  Implementation  Comparisons  Conclusions 17

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22.  Introduction  Preliminaries  RCDA-HOMO  RCDA-HETE  Analysis  Performance  Comparisons  Conclusions 22

23.  Without compromising any SN or CH ◦ Adversary can’t sign forged messages without private keys  Compromising SNs ◦ Signature required for each generated message  Compromising CHs ◦ No decryption private key is stored in a cluster ◦ Selective forwarding attack was defended 23

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26.  The base station can securely recover all sensing data rather than aggregated results, but the transmission overhead is still acceptable.  The aggregate signature scheme to ensure data authenticity and integrity 26