A NOVEL APPROACH TO ALLOW MULTIPLE RESALES OF DRM-

PROTECTED CONTENTSTarek Gaber

Dept. of Computer Science,

Faculty of Computers and Informatics,

Suez Canal University

Member of the Scientific Research Group in Egypt (SRGE)

http://www.egyptscience.net

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tmgaber@gmail.com

Prof.Aboul Ella’s Group

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Agenda

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Introduction Research Problem Existing Solutions Drawbacks of the existing solutions Our vision Proposed approach Contributions Future work

ICCES2013-Ain Shams Uni- Cairo, Egypt, 26-28 Nov 2013

Introduction I

Cryptographic Techniques could help but not enough

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Introduction II

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DRM (Digital Rights Management): Content owners

Persistent protection Prevent unauthorized access

Managing usage rights (i.e. license) E.g. expiration date, device restriction, etc.

Protect their monetary interests

Consumers Purchase licenses (from a License issuer (LI)) to access

corresponding digital contents. But can NOT resell their licenses

DRM System

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Research Problem

Problems in supporting license resellingProblems in supporting license reselling

• Put content owners’ rights at risk– Double reselling – Continued use– Reselling forged copy

• DRM feature– License is bound to device

• More problems – Must be fair for resellers and buyers

• No trust between entities

Existing Solutions

Hardware-based solutions Trusted devices are used Fair reselling addressed using offline TTP-based

approach Software-based solutions

Online service is used Fair reselling is NOT addressed using Did not address multiple resales of one license

Problems in Existing Solutions

• Hardware-based solutions

– Impose additional cost on consumers

• Software-based solutions

– Inconvenient: Play/view content online

Our Vision

Designing a license reselling solution such that: Supporting reselling

No additional hardware Play/view content offline

Not compromising content owners’ rights Secure

Non-repudiation Fairness Abuse-free

Additional attractive features Support market power

Proposed Approach

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Reseller(Alice)

Buyer(Bob)

1- Negotiation•Agree on deal terms and conditions`

2- Signing•Commit to RD terms and conditions

3- Submission•Submit a signed RD •Make payment•.LI verifications

License Issuer

(LI)

4- Activation•Create New RP for the license•Revoke Alice’s license •Send Bob’s payment to Alice •

RD

Pre-official RD

Official-RD

RD done

Handling Misbehaviour of Alice•Prevent further reselling: Blacklist•Impose a charge

Send Alice’s license to Bob

LI Verifications

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LIV1No payment

Payment is provided

LIV2

LIV3.1

LIV3.2

LIV4

Stopand

terminate the

protocol run

Payment is enough

Payment is not enough

Non-resalable (i.e. ks is not valid)

Resalable

Resold (i.e. ks is already released)

Not resold yet

LIV5

Accept and activate the submitted RD

No buyer’s signature or it is not valid

No reseller’s signature or it is not valid

Buyer’s signature is valid

Reseller's signature is valid

Submitted RD

Legitimacy check

Re-salablity Check

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Contributions

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Novel approach allowing resale of a DRM-Protected content multiple times.

The underlying security mechanism already built into existing DRM systems.

The approach enables a buyer to make sure that a license he is about to purchase is indeed resalable and has not yet resold.

Contributions

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The analysis of the approach has shown that it satisfies the specified security requirements.

The approach also can thwart potential threats and attacks that could be mounted by either a buyer or a reseller.

Future Work

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Doing a prototype for this approach to assess its performance

Thanks and Acknowledgement

Thanks and Acknowledgement

http://www.egyptscience.net

Authors Mahmoud ElGayyar, Hany ElYamany, Tarek Gaber, and Aboul

Ella Hassanien

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ThanksQuestions

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