Parametric model checking timed automata under non-Zenoness assumption

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Model Checking Timed Automata pada proses Authentikasi Security Protocol Pada Jaringan Berbasis Nirkabel

ABSTRAKSI: Protokol authentikasi EAP MD5 dan EAP TLS adalah protokol keamanan yang masih sering dijumpai pengunaannya saat ini. Protokol Keamanan tersebut menggunakan proses authentikasi pada jaringan nirkabel dengan menggunakan IEEE 802.1x sebagai media transmisinya. Terdapat 3 komponen yang berperan pada IEEE 802.1x yaitu suplican , authenticator dan authentication server. Ketiga komponen inilah yang akan dimodelkan dengan menggunakan timed automata untuk melihat kondisi yang terjadi jika dilakukan serangan dengan menggunakan man in the middle attack dan dilakukan penambahan aspek waktu pada protokol tersebut. Salah satu bentuk pengecekan terhadap model adalah dengan menggunakan timed automata. Timed Automata adalah finate automata klasik yang dapat memanipulasi waktu, berkembang terus menerus dan mensinkonisasikan dengan waktu mutlak[2]. Tugas akhir ini mengkhususkan diri pada proses memodelkan protokol authentikasi EAP MD5 dan EAP TLS dengan menggunakan Timed Automata dengan menambahkan kemungkinan retransmisi berdasarkan aspek waktu. Setelah model selesai maka berikutnya dilakukan pengecekan terhadap model berdasarkan aturan yang ada apakah dapat berjalan sesuai dengan aturan tersebut. Dari hasil verfikasi model tersebut dengan menggunakan alat UPPAAL maka dapat dilihat bahwasannya protokol authentikasi EAP MD5 dan EAP TLS dapat dimodelkan dengan menggunakan timed automata dan sesuai dengan aturan yang terdapat pada RFC protokol tersebut.Kata Kunci : EAP MD5, EAP TLS, Timed Automata, UPPAALABSTRACT: Authentication protocols EAP MD5 and EAP TLS are security protocols that are still frequently encountered use today. This Security Protocol using the process of authentication on a wireless network using the IEEE 802.1x as the transmission medium. There are three components that use a role in the IEEE 802.1x are suplican, authenticator and authentication server. These three components will be modeled using timed automata to see the condition that occurs when an attack carried out by using the man in the middle attack and carried out additional aspects of the time in the protocol. One form of model checking is use timed automata. Timed automata are classic finate automata that can manipulate time, developing continuously and synchronously with the absolute time [2]. This final project focuses on the modeling process authentication protocols EAP MD5 and EAP TLS using Timed Automata with the added possibility of retransmission based on the aspect of time. Once completed, the next model to be checked against an existing model based on whether the rules can be run in accordance with these rules. From the results verify the model using UPPAAL tool, it can be seen authentication protocols EAP MD5 and EAP TLS can be modeled using timed automata, and in accordance with the rules contained in the RFC protocol.Keyword: EAP MD5, EAP TLS, Timed Automata, UPPAA

Reducing Clocks in Timed Automata while Preserving Bisimulation

Model checking timed automata becomes increasingly complex with the increase in the number of clocks. Hence it is desirable that one constructs an automaton with the minimum number of clocks possible. The problem of checking whether there exists a timed automaton with a smaller number of clocks such that the timed language accepted by the original automaton is preserved is known to be undecidable. In this paper, we give a construction, which for any given timed automaton produces a timed bisimilar automaton with the least number of clocks. Further, we show that such an automaton with the minimum possible number of clocks can be constructed in time that is doubly exponential in the number of clocks of the original automaton.Comment: 28 pages including reference, 8 figures, full version of paper accepted in CONCUR 201

IMITATOR II: A Tool for Solving the Good Parameters Problem in Timed Automata

We present here Imitator II, a new version of Imitator, a tool implementing the "inverse method" for parametric timed automata: given a reference valuation of the parameters, it synthesizes a constraint such that, for any valuation satisfying this constraint, the system behaves the same as under the reference valuation in terms of traces, i.e., alternating sequences of locations and actions. Imitator II also implements the "behavioral cartography algorithm", allowing us to solve the following good parameters problem: find a set of valuations within a given bounded parametric domain for which the system behaves well. We present new features and optimizations of the tool, and give results of applications to various examples of asynchronous circuits and communication protocols.Comment: In Proceedings INFINITY 2010, arXiv:1010.611

Zenoness for Timed Pushdown Automata

Timed pushdown automata are pushdown automata extended with a finite set of real-valued clocks. Additionaly, each symbol in the stack is equipped with a value representing its age. The enabledness of a transition may depend on the values of the clocks and the age of the topmost symbol. Therefore, dense-timed pushdown automata subsume both pushdown automata and timed automata. We have previously shown that the reachability problem for this model is decidable. In this paper, we study the zenoness problem and show that it is EXPTIME-complete.Comment: In Proceedings INFINITY 2013, arXiv:1402.661

Testing real-time systems using TINA

The paper presents a technique for model-based black-box conformance testing of real-time systems using the Time Petri Net Analyzer TINA. Such test suites are derived from a prioritized time Petri net composed of two concurrent sub-nets specifying respectively the expected behaviour of the system under test and its environment.We describe how the toolbox TINA has been extended to support automatic generation of time-optimal test suites. The result is optimal in the sense that the set of test cases in the test suite have the shortest possible accumulated time to be executed. Input/output conformance serves as the notion of implementation correctness, essentially timed trace inclusion taking environment assumptions into account. Test cases selection is based either on using manually formulated test purposes or automatically from various coverage criteria specifying structural criteria of the model to be fulfilled by the test suite. We discuss how test purposes and coverage criterion are specified in the linear temporal logic SE-LTL, derive test sequences, and assign verdicts

Speeding up the constraint-based method in difference logic

"The final publication is available at http://link.springer.com/chapter/10.1007%2F978-3-319-40970-2_18"Over the years the constraint-based method has been successfully applied to a wide range of problems in program analysis, from invariant generation to termination and non-termination proving. Quite often the semantics of the program under study as well as the properties to be generated belong to difference logic, i.e., the fragment of linear arithmetic where atoms are inequalities of the form u v = k. However, so far constraint-based techniques have not exploited this fact: in general, Farkas’ Lemma is used to produce the constraints over template unknowns, which leads to non-linear SMT problems. Based on classical results of graph theory, in this paper we propose new encodings for generating these constraints when program semantics and templates belong to difference logic. Thanks to this approach, instead of a heavyweight non-linear arithmetic solver, a much cheaper SMT solver for difference logic or linear integer arithmetic can be employed for solving the resulting constraints. We present encouraging experimental results that show the high impact of the proposed techniques on the performance of the VeryMax verification systemPeer ReviewedPostprint (author's final draft

07241 Abstracts Collection -- Tools for the Model-based Development of Certifiable, Dependable Systems

From June 10th to June 15th 2007, the Dagstuhl Seminar 07241 ``Tools for the Model-based Development of Certifiable, Dependable Systems\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available