1. A novel DRM framework for peer-to- per music content delivery Authors: Jung-Shian Li, Che-Jen Hsieh, Cheng-Fu Hung Source: 2010, Journal of Systems and Software Speaker: Yi-Ru Lin Date: 08/12/2010 1 National Chung Hsing University

2. Outline  Introduction  Goals of this Scheme  RSA Public-key Cryptosystem  Related Works  Content Distribution  DRM  Proposed Scheme  Notations  Distribution Phase  FP Generation Phase  FP Embedding/Protection/Checking Phase  Experiment  Conclusions 2

3. INTRODUCTION 3 Goals of this Scheme RSA Public-key Cryptosystem

4.  Scalable, secure, and robust  Reduces the distribution overhead and resolves the “last piece problem”  Identify misbehaving users Goals of this Scheme 4

5. RSA Public-key Cryptosystem - 1 5  Choose two prime number p, q  Compute N = pq  Choose an integer e, and e and (p-1)(q-1) are coprime  Determine d, de ≡ 1 (mod (p-1)(q-1))  d is kept as the private key

6. RSA Public-key Cryptosystem - 2 6  p=3, q=7, n=21, (p-1)(q-1)=12, choose e=5  Determine d, ed mod 12 = 1, choose d=17  Public e=5, n=21  Encrypt: C=M^e mod n M=13, C=13^5 mod 21 = 371293  Decrypt: M=C^d mod n M=371293^17 mod 21 = 13

7. RELATED WORKS 7 Content Distribution DRM

8. 8 Content Distribution  Lagrange polynomial interpolation  Gaussian elimination

9. 9 DRM  Embedded digital fingerprint into each copy of the file  Any unauthorized distribution can be easily traced.

10. PROPOSED SCHEME 10 Notations Distribution Phase FP Generation Phase FP Embedding/Protection/Checking Phase

11. 11 Notations

12. 12 Distribution Phase Assumption Each peer in the network has a group key pair Public key: (E r, N r ) Private key: (D r, N r ) Finite Field Gaussian Elimination

13. 13 FP generation phase When DP downloads sufficient pieces, DP can reconstruct the entire music file. Public key Private key Public key Private key

14. 14 FP embedding/protection/checking phase MP3Stego Add error-correction code

15. EXPERIMENT 15 Piece Partition and Piece Reconstruction Process Signal-to-noise Ratio P2P Content Delivery

16. 16 Experiment -1 Piece partition Piece reconstruction Piece Partition and Piece Reconstruction Process Signal-to-noise ratio ( 信噪比 )

17. 17 Experiment -2 P2P content delivery

18.  RSA public-key cryptosystem  Too many parameters need to store.  Doing key exchange too many times. 18 Conclusions

19. 19