efficient design of interpretation of rel license using expert systems chun hui suen, munich...

Efficient design of Efficient design of interpretation of REL interpretation of REL license using Expert license using Expert

SystemsSystems

Chun Hui Suen, Chun Hui Suen,

Munich University of Technology,Munich University of Technology,

Institute for Data ProcessingInstitute for Data Processing

ContentsContents

ProblemsProblems Current solutionCurrent solution Proposed solutionProposed solution Offline DemoOffline Demo ComparisonComparison ConclusionConclusion

1

Rights Expression LanguageRights Expression Language

•Buy•Rent•Promotion•Share•Gift

2

DRM System

Consumer Content Provider


•Direct payment•Payment information•Try before buying

.

.

.

2

DRM System

Consumer Content Provider


Expressive REL needed for user-friendly DRM Expressive REL needed for user-friendly DRM Complicated REL license interpreterComplicated REL license interpreter

2

ProblemProblem

License

Grant

Condition

Grant

ConditionLicense

Root Grant

…

Expressive Rights description – MPEG-21 RELExpressive Rights description – MPEG-21 REL Tree-based XMLTree-based XML ComplicatedComplicated

dependanciesdependancies

3

Current solutionCurrent solution Inperative programmingInperative programming Object-orientated mappingObject-orientated mapping

License

Grant

Condition

Grant

ConditionLicense

Root Grant

… 4

Current solutionCurrent solution Inperative programmingInperative programming Object-orientated mappingObject-orientated mapping

License

Grant

Condition

Grant

ConditionLicense

Root Grant

… 4

License Object

Grant Object

Condition Object

Grant Object

Condition ObjectLicense

Object

Root Grant Object

…

Proposed SolutionProposed Solution

Knowledge based parsingKnowledge based parsing

License

Grant

Condition

Grant

ConditionLicense

Root Grant

…

Knowledgedatabase

XML - Knowledge parser

5

Proposed SolutionProposed Solution

Knowledgedatabase

6

Root grant xx xx xx

License xx xx xx

Grant xx xx xx

Condition xx xx xx

Grant xx xx xx

Condition xx xx xx

License xx xx xx

Intelligence

Rule-based matchingRule-based matching(Experts System)(Experts System)

Root grant xx xx xx

License xx xx xx

Grant xx xx xx

Condition xx xx xx

Grant xx xx xx

Condition xx xx xx

License xx xx xx

Rule

pattern action

Rule

pattern action

. . .

Inference Engine

Pattern-matching

7

Intelligence

Rule-based matchingRule-based matching (Experts System) (Experts System)

Root grant xx xx xx

License xx xx xx

Grant xx xx xx

Condition xx xx xx

Grant xx xx xx

Condition xx xx xx

License xx xx xx

Rule

pattern action

Rule

pattern action

. . .

Inference Engine

Add / Mod. /Delete

7

ImplementationImplementation

8

XMLlicense

XML parser in c++

CLIPSexpert sys.

Hypothesis

Interpretation result

Rulesbase

Input to

inte

rpre

tatio

n e

ngin

e States

phase1 phase2

•What right is requested?•Who can perform it?•What resource to use?•Under what conditions?

•System States•counters

ImplementationImplementation

9

Hypothesis is true?

Grant valid?

Issuer valid?

Conditionsfulfilled?

Principalvalid?

Resource

valid?

Operationvalid?

Root grantLicense

Grant

Condition

Root Grant

Resources

Right

keyholder

Demo – Input License 1Demo – Input License 1<rootGrant><rootGrant>

<keyholder><keyholder>Company ACompany A</keyholder></keyholder><trustedRootIssuer/><trustedRootIssuer/>

</rootGrant></rootGrant>

„„Company A“ is a trusted issuerCompany A“ is a trusted issuer

<rootGrant><rootGrant><keyholder><keyholder>johnjohn</keyholder></keyholder><possessProperty/><possessProperty/><propertyUri><propertyUri>SubscriptionSubscription</propertyUri></propertyUri>

</rootGrant></rootGrant>

““John” has property “Subscription”John” has property “Subscription”

10

Demo – Input License 2Demo – Input License 2

<license><license>

<grant><grant>

<keyholder><keyholder>johnjohn</keyholder></keyholder>

<<playplay/>/>

<digitalresource><digitalresource>somewhere.mp3somewhere.mp3</digitalresource></digitalresource>

<prerequisiteRight><prerequisiteRight>

<keyholder><keyholder>johnjohn</keyholder></keyholder>

<possessProperty/><possessProperty/>

<propertyUri><propertyUri>SubscriptionSubscription</propertyUri></propertyUri>

</prerequisiteRight></prerequisiteRight>

</grant></grant>

“ “john” allowed to “play”, only if “john” has “Subscription” propertyjohn” allowed to “play”, only if “john” has “Subscription” property

11

Demo – Input License 3Demo – Input License 3

<issuer><issuer>Company ACompany A</issuer></issuer>

</license></license>

Issuer of license is “Company A”Issuer of license is “Company A”

13

Demo – Parsed License 1Demo – Parsed License 1 (rootGrant g0)(rootGrant g0) (keyholder "Company A" g0)(keyholder "Company A" g0) (trustedRootIssuer g0)(trustedRootIssuer g0) (rootGrant g1)(rootGrant g1) (keyholder “john" g1)(keyholder “john" g1) (right possessProperty g1)(right possessProperty g1) (property "Subscription" g1)(property "Subscription" g1) (license l0)(license l0) (grant g2 l0)(grant g2 l0) (keyholder “john" g2)(keyholder “john" g2) (right play g2)(right play g2) (digitalresource "somewhere.mp3" g2)(digitalresource "somewhere.mp3" g2)

14

Demo – Parsed License 2Demo – Parsed License 2

(condition-or c0 g2)(condition-or c0 g2)

(condition c0 prerequisiteRight p0)(condition c0 prerequisiteRight p0)

(keyholder “john" p0)(keyholder “john" p0)

(right possessProperty p0)(right possessProperty p0)

(property "Subscription" p0)(property "Subscription" p0)

(issuer "Company A" l0)(issuer "Company A" l0)

(time 20060504)(time 20060504)

(database-count 5 c2)(database-count 5 c2)

(predicate 0 “john" play "somewhere.mp3")(predicate 0 “john" play "somewhere.mp3")

15

Hypothesis & states

Demo – Interpretation 1Demo – Interpretation 1

(authorized-grant g0 -1)(authorized-grant g0 -1)


(authorized-grant g2 l0)(authorized-grant g2 l0)

Grant blocks recognised as authorized/trusted15





=> (predicate p0 “john" possessProperty "Subscription")=> (predicate p0 “john" possessProperty "Subscription")

New hypothesis: Does john has the property Subscription15






(keyholder_matched p0 g1)(keyholder_matched p0 g1) - johnjohn

(op_matched p0 g1)(op_matched p0 g1) - possessProperty- possessProperty

(cond-fulfilled g1)(cond-fulfilled g1) - none- none

(resource_matched p0 g1)(resource_matched p0 g1) - “Subscription”- “Subscription”

Conditions for new predicate fulfilled15






(keyholder_matched p0 g1)(keyholder_matched p0 g1)

(op_matched p0 g1)(op_matched p0 g1)

(cond-fulfilled g1)(cond-fulfilled g1)

(resource_matched p0 g1)(resource_matched p0 g1)

(predicate-success p0)(predicate-success p0)

New hypothesis fulfilled15






(keyholder_matched p0 g1)(keyholder_matched p0 g1)

(op_matched p0 g1)(op_matched p0 g1)


(resource_matched p0 g1)(resource_matched p0 g1)

(predicate-success p0)(predicate-success p0)

(cond-true c0 prerequisiteRight p0)(cond-true c0 prerequisiteRight p0)

(cond-satisfied c0)(cond-satisfied c0)

Recursive condtion fulfilled15


(keyholder_matched 0 g2)(keyholder_matched 0 g2) - John- John

(op_matched 0 g2)(op_matched 0 g2) - playplay

(resource_matched 0 g2)(resource_matched 0 g2) - somewhere.mp3- somewhere.mp3

(cond-fulfilled g2)(cond-fulfilled g2) - has property- has property

Conditions of first grant block fulfilled16


(keyholder_matched 0 g2)(keyholder_matched 0 g2)

(op_matched 0 g2)(op_matched 0 g2)

(resource_matched 0 g2)(resource_matched 0 g2)


(predicate-success 0)(predicate-success 0)

Final hypothesis fulfilled.16

Comparison - AdvantagesComparison - Advantages

Flat structure – aids in overcoming problems of Flat structure – aids in overcoming problems of complex dependanciescomplex dependancies OOP implementation requires global data to support recursive OOP implementation requires global data to support recursive

conditioncondition

Knowledge predicate is easily stored in databaseKnowledge predicate is easily stored in database Support high-volume operationSupport high-volume operation

““Proof” of authorization can be easily generatedProof” of authorization can be easily generated Logging of reason for authorizationLogging of reason for authorization Helps in making intelligent authorization decisionsHelps in making intelligent authorization decisions

17

Comparison - DisadvantagesComparison - Disadvantages

Additional knowledge creation stageAdditional knowledge creation stage(XML – pre-processing)(XML – pre-processing)

Unable to support XML-related conditions in Unable to support XML-related conditions in MPEG-21 RELMPEG-21 REL

18

Future workFuture work

Quantitative speed testQuantitative speed test Optimization of knowledge-based approachOptimization of knowledge-based approach

Partitioning of knowledge database into clearly Partitioning of knowledge database into clearly defined sets to reduce search range for rule defined sets to reduce search range for rule matchingmatching

Support more REL commandsSupport more REL commands

19

ConclusionConclusion

Knowledge-based parsing is feasibleKnowledge-based parsing is feasible Reduce REL parser design complexityReduce REL parser design complexity

20

QuestionsQuestions

efficient design of interpretation of rel license using expert systems chun hui suen, munich...

Documents

xxxx grant

xxxx license

xxxx slide

xxxx condition

grant valid

demo input license

property subscription

subscription property