Technical Report TR-2006-09

BibliographySuwimonteerabuth, Dejvuth; Schwoon, Stefan; Esparza, Javier: Efficient Algorithms for Alternating Pushdown Systems: Application to Certificate Chain Discovery with Threshold Subjects.
University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Technical Report Computer Science No. 2006/09.
21 pages, english.
CR-SchemaD.4.6 (Operating Systems Security and Protection)
F.1.1 (Models of Computation)
F.1.2 (Modes of Computation)
KeywordsAuthorization SPKI/SDSI Pushdown Systems Alternation
Abstract

Motivated by recent applications of pushdown systems to computer security problems, we present an efficient algorithm for the reachability problem of alternating pushdown systems. Although the algorithm is exponential, a careful analysis reveals that the exponent is usually small in typical applications. We show that the algorithm can be used to compute winning regions in pushdown games. In a second contribution, we observe that the algorithm runs in polynomial time for a certain subproblem, and show that the computation of certificate chains with threshold certificates in the SPKI/SDSI authorization framework can be reduced to this subproblem. We present a detailed complexity analysis of the algorithm and its application, and report on experimental results obtained with a prototype implementation.

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Contactsuwimodh@fmi.uni-stuttgart.de
Department(s)University of Stuttgart, Institute of Formal Methods in Computer Science, Software Reliability and Security
Project(s)DFG-Projekt Älgorithms for Software Model Checking" SFB 627 Nexus, Teilprojekt A6
Entry dateDecember 13, 2006
   Publ. Computer Science