1. Secure Cloud Storage meets with Secure Network Coding
Fei Chen (Chinese University of Hong Kong, Hong Kong)
Tao Xiang (Chongqing University, China)
Yuanyuan Yang (Stony Brook University, USA)
Sherman S. M. Chow (Chinese University of Hong Kong, Hong Kong)

2. Roadmap Preliminaries Generic Construction Showcase: A Novel Protocol
Technical Obstacles
Showcase: A Novel Protocol
Extensions
Third-party Auditing
User Anonymity
Summary

3. Secure Cloud Storage (SCS)
Juels-Kaliski, Ateniese et al. (both CCS’07)
Wang, Chow, Wang, Ren, Lou (IEEE TC’13)
Yang-Jia (TPDS’13)
Wang, Chow, Li, Li (ICDCS’13)

4. SCS Protocol
User
Cloud

5. Handling Security

6. User
Cloud

7. Security Definition

8. Secure Network Coding (SNC)
Ahlswede, Cai, Li, Yeung from CUHK (IEEE TIT’00)
Li, Yeung, Cai (IEEE TIT’03); Cai-Yeung (ISIT’02)
Gkantsidis-Rodriguez (INFOCOM’06); Li, Lui, Chiu (ICNP’06)
Agrawal-Boneh (ACNS’09); Catalano et al. (PKC’12)
(many others)

9. SNC Protocol

10. Security Definition

11. Our work

12. 1. Generic Construction

13. Basic Idea

15. Optimization

16. Security

17. Data Recovery Algorithm

18. 2. A Novel SCS Protocol
Based on a recent SNC protocol by Catalano et al. (PKC’12)
First publicly verifiable secure cloud storage protocol which is provably secure (not random oracle heuristics)

19. Detailed Construction

20. Theoretical Performance
Asymptotic performance comparable to previous work

21. Experimental Performance
Benchmark (data from Wikipedia)
Storage and communication overhead

22. Computation Cost (Time is in milliseconds.)
The protocol is effective in practice.
Efficiency cost is acceptable for a standard model proof.
For protocols with security argued with random oracle heuristics, one may instantiate with larger cryptographic groups / security parameters, which results in lower efficiency anyways.

23. Supporting Third-Party Auditing
Idea: mask the returned result with randomized vectors with coefficients all 0 (zero-knowledge proof of knowledge)
[Wang, Chow, Wang, Ren, Lou (IEEE TC’13)]

24. Supporting User Anonymity
Idea: randomization again (blind signature approach)
[Wang, Chow, Li, Li (ICDCS’13)]

25. Summary Secure Cloud Storage meets with Secure Network Coding
A generic construction
A novel SCS protocol
Security definition and security proof
Support of third-party auditing and user anonymity