Model Checking Contracts A case study Gordon Pace Cristian - PowerPoint PPT Presentation

Model Checking Contracts A case study Gordon Pace Cristian Prisacariu Gerardo Schneider gordon.pace@um.edu.mt cristi@ifi.uio.no gerardo@ifi.uio.no Department of Informatics, University of Oslo ATVA’07 Tokyo, Japan October 22-25, 2007 university-logo Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 1 / 24

Contracts “A contract is a binding agreement between two or more persons that is enforceable by law.” [Webster on-line] university-logo Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 2 / 24

Contracts “A contract is a binding agreement between two or more persons that is enforceable by law.” [Webster on-line] This deed of Agreement is made between: 1. [name] , from now on referred to as Provider and 2. the Client . INTRODUCTION 3. The Provider is obliged to provide the Internet Services as stipulated in this Agreement . 4. DEFINITIONS a) Internet traffic may be measured by both Client and Provider by means of Equipment and may take the two values high and normal . OPERATIVE PART 1. The Client shall not supply false information to the Client Relations Department of the Provider . 2. Whenever the Internet Traffic is high then the Client must pay [ price ] immediately, or the Client must notify the Provider by sending an e-mail specifying that he will pay later. 3. If the Client delays the payment as stipulated in 2, after notification he must immediately lower the Internet traffic to the normal level, and pay later twice (2 ∗ [ price ] ). 4. If the Client does not lower the Internet traffic immediately, then the Client will have to pay 3 ∗ [ price ] . 5. The Client shall, as soon as the Internet Service becomes operative, submit within seven (7) university-logo days the Personal Data Form from his account on the Provider ’s web page to the Client Relations Department of the Provider . Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 2 / 24

Contracts We call the above a conventional contract An e-contract is a machine-readable contract Two scenarios: 1 Obtain an e-contract from a conventional contract Context: legal (e.g. financial) contracts 2 Write the e-contract directly in a formal language Context: web services, components, OO, etc Definition A contract is a document which engages several parties in a transaction and stipulates their (conditional) obligations, rights, and prohibitions, as well as penalties in case of contract violations. university-logo A better name: ‘deontic’ e-contracts Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 3 / 24

Aim and Motivation Use deontic e-contracts to ‘rule’ services exchange 1 Give a formal language for specifying/writing contracts 2 Analyze contracts “internally” Detect contradictions/inconsistencies statically Determine the obligations (permissions, prohibitions) of a signatory Detect superfluous contract clauses 3 Develop a theory of contracts Contract composition Subcontracting Conformance between a contract and the governing policies Meta-contracts (policies) 4 Monitor contracts Run-time system to ensure the contract is respected In case of contract violations, act accordingly university-logo Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 4 / 24

Outline The Contract Language CL 1 Model Checking Contracts 2 Final Remarks 3 university-logo Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 5 / 24

Outline The Contract Language CL 1 Model Checking Contracts 2 Final Remarks 3 university-logo Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 6 / 24

The Contract Specification Language CL C ontract := D ; C C := C O | C P | C F | C ∧ C | [ α ] C | � α �C | C U C | � C | � C C O := O ( α ) | C O ⊕ C O C P := P ( α ) | C P ⊕ C P C F := F ( α ) | C F ∨ [ α ] C F O ( α ) , P ( α ) , F ( α ) specify obligation, permission (rights), and prohibition (forbidden) over actions α are actions given in the definition part D + choice · concatenation (sequencing) & concurrency φ ? test ∧ , ∨ , and ⊕ are conjunction, disjunction, and exclusive disjunction [ α ] and � α � are the action parameterized modalities of dynamic logic university-logo U , � , and � correspond to temporal logic operators Gerardo Schneider (UiO) Model Checking Contracts ATVA’07 Tokyo, Japan 7 / 24

Model Checking Contracts A case study Gordon Pace Cristian - PowerPoint PPT Presentation

Model Checking Contracts A case study Gordon Pace Cristian Prisacariu Gerardo Schneider gordon.pace@um.edu.mt cristi@ifi.uio.no gerardo@ifi.uio.no Department of Informatics, University of Oslo ATVA07 Tokyo, Japan October 22-25, 2007

Solving Operating-Systems Problems with Probabilistic Model Checking Hendrik Tews Institute for

Statistical Statistical Statistical Model Statistical Model Model Checking Model Checking

Hoare Logic and Model Checking Model Checking Lecture 11: Model checking for Computation Tree

Bounded Model Checking bmc Revision: 1.11 1 [BiereCimattiClarkeZhu99] uses SAT for model

CTL Chapter 6 Part 2 Overview Review CTL Model Checking CTL model Checking algorithms

Probabilistic model checking in practice: Case studies with PRISM Marta Kwiatkowska School of

Hoare Logic and Model Checking Model Checking But perhaps theres a clever way of

Hoare Logic and Model Checking 1. You should be able to model simple systems in NuSMV, an LTL

Software Model Checking Using Bogor Software Model Checking Using Bogor a Modular and

Software Model Checking Using Bogor Software Model Checking Using Bogor a Modular and

Software Model Checking Using Bogor Software Model Checking Using Bogor a Modular and

2.6 Case Study: Atmosphere Model In the next three sections, we develop parallel algorithms for

Case study 2 Case study 2 Case study 2 Case study 2 Former Industrial Site, London: How has

Modeling and Analyzing Concurrent Systems using Model Checking Robert B. France 1 What is

Automated Reasoning LTL Model Checking Alan Bundy Automated Reasoning LTL Model Checking

Model Checking: the Interval Way Alberto Molinari ( j.w. with L. Bozzelli, A. Montanari, A. Peron,

Hoare Logic and Model Checking Model Checking Lecture 7: Introduction and background Dominic

Hoare Logic and Model Checking Model Checking See NuSMV homepage to download: http://nusmv.fbk.eu/

CASE STUDY III EVALUATING MODEL RISK WITHIN THE BLACKSCHOLES FRAMEWORK Limiting Model Risk

Probabilisti tic Model Checking in Practi tice Dave Parker Oxford University

Hoare Logic and Model Checking Model Checking Lecture 10: Computation Tree Logic (CTL) Dominic

Towards efficient model checking for variants of ATL under different semantics Wojciech Penczek

Perverse Incentives in Security Contracts: A Case Study in the Colombian Power Grid Carlos

Model Checking in Systems Biology s Brim and Milan ska and David Lubo Ce Safr