ICEC 2002 A Watermarking Infrastructure for Digital Rights Protection Presenter S.C. Cheung [email protected] [email protected] Department of Computer Science

ICEC 2002ICEC 2002A Watermarking Infrastructure for A Watermarking Infrastructure for

Digital Rights ProtectionDigital Rights Protection

Presenter Presenter S.C. Cheung S.C. Cheung sccscc@@cscs..ustust..hkhk

Department of Computer ScienceDepartment of Computer ScienceHong Kong University of Science and TechnologyHong Kong University of Science and Technology

Co-authors Co-authors Hanif Curreem Hanif Curreem [email protected]@cs.ust.hk

Dickson K.W. Chiu Dickson K.W. Chiu [email protected]@cse.cuhk.hk

22ICEC2002 - sccICEC2002 - scc A Watermarking Infrastructure for DigitA Watermarking Infrastructure for Digital Rights Protectional Rights Protection

OutlineOutline

Watermarking InfrastructureWatermarking Infrastructure

Research IssuesResearch Issues

Three Phases of Watermarking ProtocolThree Phases of Watermarking Protocol Watermark AcquisitionWatermark Acquisition Purchase TransactionsPurchase Transactions Dispute ResolutionDispute Resolution

Watermarking Protocol Meeting ebXMLWatermarking Protocol Meeting ebXML

Conclusion & Future WorkConclusion & Future Work


IntroductionIntroduction

Digital rights enforcement has drawn much attention Digital rights enforcement has drawn much attention latelylately Billions of dollars are lost annuallyBillions of dollars are lost annually P2P applications promote unauthorized copyingP2P applications promote unauthorized copying

Why?Why? Digital contents are easy to duplicate without loss Digital contents are easy to duplicate without loss

in qualityin quality Availability of powerful compression techniques Availability of powerful compression techniques

that can reduce file size effectively (MP3, DivX)that can reduce file size effectively (MP3, DivX)


Introduction (con’t)Introduction (con’t)

Two copyrights protection approaches:Two copyrights protection approaches: CryptographyCryptography

Transform digital contents into unperceivable formatTransform digital contents into unperceivable format

Provides effective access controlProvides effective access control

Decrypted content is vulnerable to recordingDecrypted content is vulnerable to recording Digital WatermarkingDigital Watermarking

Hide the copyright control information into digital Hide the copyright control information into digital content by modification the content itselfcontent by modification the content itself

Watermarks are difficult to be removed from contents Watermarks are difficult to be removed from contents without the knowledge of the insertion key. without the knowledge of the insertion key.


Introduction (con’t)Introduction (con’t)

Application of digital watermarking to Application of digital watermarking to manage digital rights in order to:manage digital rights in order to:

Identify and claim the copyrights ownershipIdentify and claim the copyrights ownership

Identify the origin of illegal distribution Identify the origin of illegal distribution


Digital Watermarking is originated from Steganography


Digital WatermarkingDigital Watermarkinginsertion detection


Watermarking InfrastructureWatermarking Infrastructure

PurchaseTransaction

Request and generate

watermark certificate

Buyer

WatermarkCertification

Authority

Get watermarkedcontents

Merchant Content Provider

Submit evidence of digital rights violation

Judge


Research Issues in Watermarking ProtocolResearch Issues in Watermarking Protocol

PhasesPhases IssuesIssues

Watermark acquisitionWatermark acquisition - Secrecy of watermarks- Secrecy of watermarks

Purchase transactionsPurchase transactions - Buyers cannot be trustedBuyers cannot be trusted- Merchants cannot be trustedMerchants cannot be trusted

Dispute resolutionDispute resolution - Buyers cannot be trustedBuyers cannot be trusted- Merchants cannot be trustedMerchants cannot be trusted- Judge cannot be trustedJudge cannot be trusted


ProblemProblem

Identify the origin of illegal distributionIdentify the origin of illegal distribution Buyer of the origin is liableBuyer of the origin is liable Buyer watermark are analogous to a Buyer watermark are analogous to a

private keyprivate key Could we protect buyer’s watermark in a Could we protect buyer’s watermark in a

purchase transaction to prevent merchants purchase transaction to prevent merchants and content distributors from abusing the and content distributors from abusing the watermark?watermark?


Solution SketchSolution Sketch

Buyers need not release their watermarksBuyers need not release their watermarks

Instead, buyers release an encrypted version Instead, buyers release an encrypted version of their watermarksof their watermarks

So, how does a merchant or content So, how does a merchant or content distributor validate an encrypted watermark?distributor validate an encrypted watermark?

Trusted Watermark Certification AuthorityTrusted Watermark Certification Authority

Use watermark certificate to protect the Use watermark certificate to protect the integrity of encrypted watermarkintegrity of encrypted watermark


Enhanced Watermarking InfrastructureEnhanced Watermarking Infrastructure

PurchaseTransaction

Request and generate

watermark certificate

Buyer

WatermarkCertification

Authority

Get watermarkedcontents

Merchant Content Provider

Submit evidence of digital rights violation

Judge


Data Structure of Watermark CertificateData Structure of Watermark Certificate

Watermark Certificate Response

Watermark Certificate (WCertB)

Watermark(W)

EncryptedWatermark

EKB(W)

Watermark Certificate

Request

PKI Certificate (CertB)

Public Key (KB)

Buyer1

1

1

1

1 1

1

1

Watermark Certification

Authority

1

generated by1 *

refers to refers to

refers to

Sign(WCertB)

encrypt

1

aggregation binary association

ternary associationproduces


apply for watermark certificate


Requestgenerate watermark


WCertB

obtain PKI certificate

store certificate

BuyerWatermark Certification

Authority

Watermark AcquisitionWatermark Acquisition


forward certificateWatermark Certificate

WCertB

decrypt contents

Encrypted Watermarked Contents EKB(X’ σW)

place order

Buyer Merchant Content ProviderWatermark Certificate

WCertB

verify

generate transaction identifier (V)

update license database with V

encrypt contents

insert encrypted watermark

EncryptedContents EKB(X’)

deliver contents

Decrypted Watermarked

Contents(X’ σW)

Encrypted Watermarked

Contents EKB(X’ σW)

permutate watermark

Permutated Watermark

EKB(σW)

Purchase TransactionPurchase Transaction


Dispute ResolutionDispute Resolution

encrypt X” by EKB

Evidence Response

(σ, WCertB)

discover a suspected content (X”)

Law Enforcer / Judge Content Provider

retrieve the transaction identifier (V) from X”

lookup permutation function σ and watermark certificate (WCertB) from database

send evidence σ & WCertB

Encrypted DocumentEKB(X”)

data objects

activities

Evidence Request (X”)

submit X”

retrieve public key EKB retrieve encrypted

watermark EKB(W)

apply permutationfunction σ

Permutated Encrypted Watermark

EKB(σW)

detect existence of EKB(σW) in EKB(X”)

[no]

X” originates from theend user of WCertB

[yes]


Watermarking Protocol Meeting ebXMLWatermarking Protocol Meeting ebXML


ConclusionConclusionWe have proposed a watermarking We have proposed a watermarking protocol infrastructure thatprotocol infrastructure that supports three common roles in B2C e-supports three common roles in B2C e-

commerce model: customers, merchants and commerce model: customers, merchants and content providers;content providers;

does not require trusts on these parties in the does not require trusts on these parties in the protection of watermarks; protection of watermarks;

assumes a trusted watermark certification assumes a trusted watermark certification authority and the use of watermark certificatesauthority and the use of watermark certificates


Future WorkFuture WorkStudy the effectiveness of our protocol with respect Study the effectiveness of our protocol with respect to various watermarking schemesto various watermarking schemes

Adapt the techniques to digital contents in Adapt the techniques to digital contents in JPEG2000 formatJPEG2000 format

Study the integration of watermarking protocols and Study the integration of watermarking protocols and payment protocolspayment protocols

Studies are being carried out to apply watermarking Studies are being carried out to apply watermarking protocol for enterprise document management protocol for enterprise document management (preliminary results to appear in HICSS-36)(preliminary results to appear in HICSS-36)

Questions and AnswersQuestions and Answers

[email protected]@cs.ust.hk

[email protected]@cse.cuhk.hk


Supplementary Slides (Q&A)Supplementary Slides (Q&A)Permutation functionPermutation functionvoid permutefunc(VLONG wmark[], int size, int seed)void permutefunc(VLONG wmark[], int size, int seed){{

int i, index1, index2;int i, index1, index2;srand(seed);srand(seed);for (i=0; i < rand() % 100 + 50)for (i=0; i < rand() % 100 + 50) // min. 50 times, max 150 times// min. 50 times, max 150 times{{

VLONG tmp;VLONG tmp;index1=rand()%size;index1=rand()%size;index2=rand()%size;index2=rand()%size;// swap the two watermark coefficient// swap the two watermark coefficienttmp = wmark[index1];tmp = wmark[index1];wmark[index1]=wmark[index2];wmark[index1]=wmark[index2];wmark[index2]=tmp;wmark[index2]=tmp;

}}} }


Supplementary Slides (Q&A)Supplementary Slides (Q&A)

Watermark generation and insertion Watermark generation and insertion Privacy homomorphismPrivacy homomorphism

If the watermark insertion operation is:If the watermark insertion operation is: XXW = { xW = { x11(1+αw(1+αw11), x), x22(1+αw(1+αw22),…, x),…, x10001000(1+αw(1+αw10001000)})}

Then we have,Then we have, (E(E((xx)) E E((yy)) mod n = )) mod n = EE((x x y y) )

Therefore we can insert watermark in the Therefore we can insert watermark in the encrypted domain:encrypted domain:

EEKBKB(X’(X’σ(W)) = Eσ(W)) = EKBKB(X’) (X’) σ(Eσ(EKBKB(W)) (W))

Documents

ICEC 2002 A Watermarking Infrastructure for Digital Rights Protection Presenter S.C. Cheung [email protected] [email protected] Department of Computer Science