A Study of Key Management for Access Control in Hierarchy

1. A Study of Key Management for Access Control in Hierarchy Min-Shiang Hwang Department of Computer Science and Information Engineering Asia University

2. Outline • Introduction • Research motivation • Related works • Requirements • Research objectives • The first proposed scheme • Review of Odelu et al.’s scheme (2013) • The first our proposed scheme • Analysis • The second proposed scheme • Review of Odelu et al.’s scheme (2014) • The second our proposed scheme • Analysis • Conclusions and future works

3. Introduction- Research Motivation KAU • Hierarchical structure • Data-sharing becomes easier • Information security • Avoid unauthorized access • Encrypt the files • Key management President of AU KIET KMBA Dean of College IET Dean of College MBA KIE KEE Chair of Department IE Chair of Department EE KC KA KB KD Prof. B Prof. C Prof. D Prof. A CA=EKA(FA) CB=EKB(FB) CC=EKC(FC)

4. Introduction- Related works

5. Requirements • Simple and efficient: Keys generation and derivation • Security: Forward security, common attack • Flexible: Dynamic key management problems • Efficient: The alternation occurring in lowerlevel classes • Small: Public parameters • Minimum: Computational cost

6. Research objectives • Design a key management scheme for access control in the general hierarchical structure. • Design a key management scheme for access control in the large leaf class hierarchical structure.

7. Review of Odelu et al.’s scheme (2013)

8. Key generation phase(1)

9. Key generation phase (2)

10. Key derivation phase (1)

11. Key derivation phase (2)

12. Key derivation phase (3)

13. The first our proposed scheme

14. Key generation phase (1)

15. Key generation phase (2)

16. Key derivation phase (1)

17. Key derivation phase (2)

18. Key derivation phase (3)

19. Dynamic key management- Add

20. Dynamic key management- Delete

21. Security analysis

22. Storage complexity analysis [33] M. Nikooghadam, A. Zakerolhosseini, M.E. Moghaddam, Efficient utilization of elliptic curve cryptosystem for hierarchical access control, Journal of Systems and Software, 83 (2010) 1917-1929. [38] S. Wu, K. Chen, An efficient key-management scheme for hierarchical access control in e-medicine system, Journal of medical systems, 36 (2012) 2325-2337. [39] V. Odelu, A.K. Das, A. Goswami, An effective and secure key-management scheme for hierarchical access control in E-medicine system, Journal of medical systems, 37 (2013) 9920.

24. Computational complexity analysis [33] M. Nikooghadam, A. Zakerolhosseini, M.E. Moghaddam, Efficient utilization of elliptic curve cryptosystem for hierarchical access control, Journal of Systems and Software, 83 (2010) 1917-1929. [38] S. Wu, K. Chen, An efficient key-management scheme for hierarchical access control in e-medicine system, Journal of medical systems, 36 (2012) 2325-2337. [39] V. Odelu, A.K. Das, A. Goswami, An effective and secure key-management scheme for hierarchical access control in E-medicine system, Journal of medical systems, 37 (2013) 9920.

25. Review of Odelu et al.’s scheme (2014)

26. Key generation phase (1) …

27. Key generation phase (2)

28. Key derivation phase (1) …

29. Key derivation phase (2) …

30. Key derivation phase (3) …

31. The second our proposed scheme

32. Key generation phase (1) … Public parameters

33. Key generation phase (2)

34. Key derivation phase (1) …

35. Key derivation phase (2) …

36. Key derivation phase (3) …

37. Key derivation phase (4) …

38. Key derivation phase (5) …

39. Dynamic key management- Add (1) …

40. Dynamic key management- Add (2) …

41. Dynamic key management- Delete …

42. Security analysis

43. Storage complexity analysis [3] M.S. Hwang, W.P. Yang, Controlling access in large partially ordered hierarchies using cryptographic keys, Journal of Systems and Software, 67 (2003) 99-107. [6] J.W. Lo, M.S. Hwang, C.H. Liu, An efficient key assignment scheme for access control in a large leaf class hierarchy, Information Sciences, 181 (2011) 917-925. [7] V. Odelu, A.K. Das, A. Goswami, A secure effective key management scheme for dynamic access control in a large leaf class hierarchy, Information Sciences, 269 (2014) 270-285. [8] S.G. Akl, P.D. Taylor, Cryptographic solution to a problem of access control in a hierarchy, ACM Trans. Comput. Syst., 1 (1983) 239-248.

44. Computational complexity analysis [3] M.S. Hwang, W.P. Yang, Controlling access in large partially ordered hierarchies using cryptographic keys, Journal of Systems and Software, 67 (2003) 99-107. [6] J.W. Lo, M.S. Hwang, C.H. Liu, An efficient key assignment scheme for access control in a large leaf class hierarchy, Information Sciences, 181 (2011) 917-925. [7] V. Odelu, A.K. Das, A. Goswami, A secure effective key management scheme for dynamic access control in a large leaf class hierarchy, Information Sciences, 269 (2014) 270-285. [8] S.G. Akl, P.D. Taylor, Cryptographic solution to a problem of access control in a hierarchy, ACM Trans. Comput. Syst., 1 (1983) 239-248.

45. Conclusions and future works • First proposed scheme • We proposed an improved Odelu et al.’s (2013) method which reduces the computational cost, but we sacrifice the storage space. • However, our proposed scheme in the large leaf node hierarchy causes the large numbers of public parameters. • Second proposed scheme • In Odelu et al.’s scheme (2014), adding a new security class which is immediate predecessor of a leaf node has to change the leaf node’s secret key. • We improved Lo et al.’s and Odelu et al.’s (2014) methods to use two stages to derive the secret key of the leaf node. trades the storage space for the computational cost. • Design the perfect scheme to fulfill the requirements, which is more efficient and flexible.