Reference:

Dejvuth Suwimonteerabuth, Stefan Schwoon, and Javier Esparza. Efficient algorithms for alternating pushdown systems: Application to certificate chain discovery with threshold subjects. Technical Report 2006/09, Universität Stuttgart, Fakultät Informatik, Elektrotechnik und Informationstechnik, 2006.

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.

Suggested BibTeX entry:

@techreport{SSE06a,
    author = {Dejvuth Suwimonteerabuth and Stefan Schwoon and Javier Esparza},
    institution = {Universit{\"a}t Stuttgart, Fakult\"at Informatik, Elektrotechnik und Informationstechnik},
    number = {2006/09},
    title = {Efficient Algorithms for Alternating Pushdown Systems: Application to Certificate Chain Discovery with Threshold Subjects},
    year = {2006}
}