ICEC 2002 A Watermarking Infrastructure for Digital Rights Protection Presenter S.C. Cheung Department of Computer Science Hong Kong University of Science and Technology Co-authors Hanif Curreem Dickson K.W. Chiu

2ICEC scc A Watermarking Infrastructure for Digital Rights Protection Outline Watermarking Infrastructure Research Issues Three Phases of Watermarking Protocol Watermark Acquisition Watermark Acquisition Purchase Transactions Purchase Transactions Dispute Resolution Dispute Resolution Watermarking Protocol Meeting ebXML Conclusion & Future Work

3ICEC scc A Watermarking Infrastructure for Digital Rights Protection Introduction Digital rights enforcement has drawn much attention lately Billions of dollars are lost annually Billions of dollars are lost annually P2P applications promote unauthorized copying P2P applications promote unauthorized copyingWhy? Digital contents are easy to duplicate without loss in quality Digital contents are easy to duplicate without loss in quality Availability of powerful compression techniques that can reduce file size effectively (MP3, DivX) Availability of powerful compression techniques that can reduce file size effectively (MP3, DivX)

4ICEC scc A Watermarking Infrastructure for Digital Rights Protection Introduction (con’t) Two copyrights protection approaches: Cryptography Cryptography Transform digital contents into unperceivable format Provides effective access control Decrypted content is vulnerable to recording Digital Watermarking Digital Watermarking Hide the copyright control information into digital content by modification the content itself Watermarks are difficult to be removed from contents without the knowledge of the insertion key.

5ICEC scc A Watermarking Infrastructure for Digital Rights Protection Introduction (con’t) Application of digital watermarking to manage digital rights in order to: Identify and claim the copyrights ownership Identify and claim the copyrights ownership Identify the origin of illegal distribution  Identify the origin of illegal distribution 

6ICEC scc A Watermarking Infrastructure for Digital Rights Protection Digital Watermarking is originated from Steganography

7ICEC scc A Watermarking Infrastructure for Digital Rights Protection Digital Watermarking insertiondetection

8ICEC scc A Watermarking Infrastructure for Digital Rights Protection Watermarking Infrastructure

9ICEC scc A Watermarking Infrastructure for Digital Rights Protection Research Issues in Watermarking Protocol PhasesIssues Watermark acquisition - Secrecy of watermarks Purchase transactions - Buyers cannot be trusted - Merchants cannot be trusted Dispute resolution - Buyers cannot be trusted - Merchants cannot be trusted - Judge cannot be trusted

10ICEC scc A Watermarking Infrastructure for Digital Rights Protection Problem Identify the origin of illegal distribution Buyer of the origin is liable Buyer of the origin is liable Buyer watermark are analogous to a private key Buyer watermark are analogous to a private key  Could we protect buyer’s watermark in a purchase transaction to prevent merchants and content distributors from abusing the watermark?

11ICEC scc A Watermarking Infrastructure for Digital Rights Protection Solution Sketch Buyers need not release their watermarks Instead, buyers release an encrypted version of their watermarks So, how does a merchant or content distributor validate an encrypted watermark? Trusted Watermark Certification Authority Use watermark certificate to protect the integrity of encrypted watermark

12ICEC scc A Watermarking Infrastructure for Digital Rights Protection Enhanced Watermarking Infrastructure

13ICEC scc A Watermarking Infrastructure for Digital Rights Protection Data Structure of Watermark Certificate

14ICEC scc A Watermarking Infrastructure for Digital Rights Protection apply for watermark certificate Watermark Certificate Request generate watermark Watermark Certificate WCert B obtain PKI certificate store certificate Buyer Watermark Certification Authority Watermark Acquisition

15ICEC scc A Watermarking Infrastructure for Digital Rights Protection forward certificate Watermark Certificate WCert B decrypt contents Encrypted Watermarked Contents E KB (X’  σW) place order BuyerMerchantContent Provider Watermark Certificate WCert B verify generate transaction identifier (V) update license database with V encrypt contents insert encrypted watermark Encrypted Contents E KB (X’) deliver contents Decrypted Watermarked Contents (X’  σW) Encrypted Watermarked Contents E KB (X’  σW) permutate watermark Permutated Watermark E KB (σW) Purchase Transaction

16ICEC scc A Watermarking Infrastructure for Digital Rights Protection Dispute Resolution encrypt X” by E KB Evidence Response ( σ, WCert B ) discover a suspected content (X”) Law Enforcer / JudgeContent Provider retrieve the transaction identifier (V) from X” lookup permutation function σ and watermark certificate (WCert B ) from database send evidence σ & WCert B Encrypted Document E KB (X”) data objects activities Evidence Request (X”) submit X” retrieve public key E KB retrieve encrypted watermark E KB (W) apply permutation function σ Permutated Encrypted Watermark E KB ( σ W) detect existence of E KB ( σ W) in E KB (X”) [no] X” originates from the end user of WCert B [yes]

17ICEC scc A Watermarking Infrastructure for Digital Rights Protection Watermarking Protocol Meeting ebXML

18ICEC scc A Watermarking Infrastructure for Digital Rights Protection Conclusion We have proposed a watermarking protocol infrastructure that supports three common roles in B2C e- commerce model: customers, merchants and content providers; supports three common roles in B2C e- commerce model: customers, merchants and content providers; does not require trusts on these parties in the protection of watermarks; does not require trusts on these parties in the protection of watermarks; assumes a trusted watermark certification authority and the use of watermark certificates assumes a trusted watermark certification authority and the use of watermark certificates

19ICEC scc A Watermarking Infrastructure for Digital Rights Protection Future Work Study the effectiveness of our protocol with respect to various watermarking schemes Adapt the techniques to digital contents in JPEG2000 format Study the integration of watermarking protocols and payment protocols Studies are being carried out to apply watermarking protocol for enterprise document management (preliminary results to appear in HICSS-36)

Questions and Answers

21ICEC scc A Watermarking Infrastructure for Digital Rights Protection Supplementary Slides (Q&A) Permutation function void permutefunc(VLONG wmark[], int size, int seed) { int i, index1, index2; srand(seed); for (i=0; i < rand() % )// min. 50 times, max 150 times { VLONG tmp; index1=rand()%size;index2=rand()%size; // swap the two watermark coefficient tmp = wmark[index1]; wmark[index1]=wmark[index2];wmark[index2]=tmp;}}

22ICEC scc A Watermarking Infrastructure for Digital Rights Protection Supplementary Slides (Q&A) Watermark generation and insertion Privacy homomorphism If the watermark insertion operation is: X  W = { x 1 (1+αw 1 ), x 2 (1+αw 2 ),…, x 1000 (1+αw 1000 )} X  W = { x 1 (1+αw 1 ), x 2 (1+αw 2 ),…, x 1000 (1+αw 1000 )} Then we have, (E(x)  E(y)) mod n = E(x  y) (E(x)  E(y)) mod n = E(x  y) Therefore we can insert watermark in the encrypted domain: E KB (X’  σ(W)) = E KB (X’)  σ(E KB (W)) E KB (X’  σ(W)) = E KB (X’)  σ(E KB (W))