Reactive Policies for the Semantic Web* Piero A. Bonatti Universita di Napoli Federico II, Italy Philipp Kärger L3S Research Center, Hannover, Germany Daniel Olmedilla Telefonica R&D, Madrid, Spain * The authors' efforts were partly funded by the European COST Action IC0801 ``Agreement Technologies'' Philipp Kärger - L3S Research Center 17/01/19

Outline Motivation for reactive policies Background (non-reactive) Semantic Web policies Trust Negotiation Reactive Semantic Web Policies Implementation: Reactive Policies on Skype Future Work and Conclusions Philipp Kärger - L3S Research Center 17/01/19

Philipp Kärger - L3S Research Center 17/01/19

Behavior on the Semantic Web limited support for semantic behavior definition rather focus on static knowledge typically expressed by Semantic Web policies Rei: has(X, right(service, graduateStudent(X, ’UMBC’))) Protune: allow(buy(Resource))  credential(C), valid_credit_card(C), accepted_credit_card(C). KAoS: It is permitted for actor X to perform action Y in context Z. Philipp Kärger - L3S Research Center 17/01/19

 Reactive Semantic Web Policies rather focused on access control and trust not easy to express something like Events (not just requests) reactions and “restricted” allowance (not just allow/deny) some sort of reasoning  Reactive Semantic Web Policies “A call on Skype from an untrustworthy person shall be blocked and turned into a chat.” Philipp Kärger - L3S Research Center 17/01/19

Background Philipp Kärger - L3S Research Center 17/01/19

Semantic Web Policies “declarative description of the behavior of a system” well-defined semantics shared vocabulary distributed evidences allow(read(“slides.ppt”),User)  isStudent(User). isStudent(Person)  credential(Person, Credential), Credential.issuer = “uni−hannover”, Credential.type = “studentid “. Philipp Kärger - L3S Research Center 17/01/19

Trust Negotiation establishes trust with strangers university student Trust Negotiation establishes trust with strangers collaborative fulfillment of the parties’ policies evidences are collected and shared Philipp Kärger - L3S Research Center 17/01/19

Reactive Semantic Web Policies A language for Reactive Semantic Web Policies Philipp Kärger - L3S Research Center 17/01/19

Event Condition Action rules borrowing an old idea: ON event IF condition DO action ON a skype call arrives IF caller is a student and it is not Wednesday DO turn call into a chat ON callArrives(Time,Call,Caller) IF isStudent(Caller) not isWednesday(Time) DO turnCallIntoChat(Call,Caller) Philipp Kärger - L3S Research Center 17/01/19

ON callArrives(Time,Call,Caller) IF isStudent(Caller) not isWednesday(Time) DO turnCallIntoChat(Call,Caller) Event definition rules Action definition rules Implication rules callArrives(X,Y,Z)  callArrivesOnSkype(X,Y,Z). turnCallIntoChat(Call,User)  cancelCall(Call), openChat(User). isStudent(Person)  credential(Person, Credential), Credential.issuer = “uni−hannover”, Credential.type = “studentid “. Philipp Kärger - L3S Research Center 17/01/19

Semantics ON callArrives(Time,Call,Caller) IF isStudent(Caller), not isWednesday(Time) DO turnCallIntoChat(Call,Caller) callArrives(X,Y,Z)  callArrivesOnSkype(X,Y,Z). turnCallIntoChat(Call,User)  cancelCall(Call), openChat(User). isStudent(Person)  credential(Person, Credential), Credential.issuer = “uni−hannover”, Credential.type = “studentid “. Philipp Kärger - L3S Research Center 17/01/19

Strong and lightweight evidences Strong evidences digitally signed credentials Lightweight evidences unproven facts like a license agreement age or address (html forms) password data gathered from the Semantic Web isStudent(Person)  credential(Person, Credential), Credential.issuer = “uni−hannover”, Credential.type = “studentid “. isAdult(Person)  declaration(Person, Age), Age > 18. isFOAFFriend(Person)  in([Friend], FOAFWrapper : getFOAFFriends()), Person = Friend. Philipp Kärger - L3S Research Center 17/01/19

Integration of (Semantic) Web sources isFOAFFriend(Person)  in([Friend], FOAFWrapper : getFOAFFriends()), Person = Friend. Philipp Kärger - L3S Research Center 17/01/19

Reactive Semantic Web Policies - Summary declarative policy language for reactive policies well-defined semantics strong and lightweight evidences seamless integration of (Semantic) Web sources Philipp Kärger - L3S Research Center 17/01/19

SPoX – Skype Policy Extension Implementation SPoX – Skype Policy Extension Philipp Kärger - L3S Research Center 17/01/19

Philipp Kärger - L3S Research Center 17/01/19

SPoX – a Skype Policy Extension “Driving the behavior of Skype” Reactive policies define who is allowed to do what which/whose notification shows up considers the Social Context Skype is extended by a reactive policy engine connector to (Semantic) Web sources channel for negotiations Philipp Kärger - L3S Research Center 17/01/19

Defining Reactive Policies in SPoX Philipp Kärger - L3S Research Center 17/01/19

Architecture of SPoX Philipp Kärger - L3S Research Center 17/01/19

Strong and lightweight evidences in action Strong evidences credentials are shared through the game channel Lightweight evidences used to identify people across Social Networks used to transfer passwords Philipp Kärger - L3S Research Center 17/01/19

Conclusions & Future Work Philipp Kärger - L3S Research Center 17/01/19

Future Work exploit authentication means (OpenID, FOAF+SSL, etc.) integrate other Semantic Web sources handle conflicting policy rules Philipp Kärger - L3S Research Center 17/01/19

Conclusions Reactive behavior description and trust features are isolated on the Semantic Web Reactive Semantic Web policies combines both: reactive rule reasoning and upper layers of trust on the SW stack Provided a framework for reactive Semantic Web policies establishes trust based on exchange of evidences features formal language definition Provided Implementation for the semantic behavior control in Skype Philipp Kärger - L3S Research Center 17/01/19

Thanks for your attention. www.L3S.de/~kaerger/SPoX Philipp Kärger L3S Research Center kaerger@L3S.de www.L3S.de/~kaerger Philipp Kärger - L3S Research Center 17/01/19