# Intruders with Caps

3 CASSIS - Combination of approaches to the security of infinite states systems
FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174), INRIA Lorraine, LORIA - Laboratoire Lorrain de Recherche en Informatique et ses Applications
Abstract : In the analysis of cryptographic protocols, a "treacherous" set of terms is one from which an intruder can get access to what was intended to be secret, by adding on to the top of a sequence of elements of this set, a "cap" ormed of symbols legally part of his/her knowledge. In this paper, we give sufficient conditions on the rewrite system modeling the intruder's abilities, such as using encryption and decryption functions, to ensure that it is decidable if such caps exist. The following classes of intruder systems are studied: linear, dwindling, Delta-strong, and optimally reducing; and depending on the class considered, the cap problem (find a cap for a given set of terms'') is shown respectively to be in P, NP-complete, decidable, and undecidable.
Document type :
Conference papers

https://hal.archives-ouvertes.fr/hal-00468721
Contributor : Siva Anantharaman <>
Submitted on : Wednesday, March 31, 2010 - 2:29:10 PM
Last modification on : Thursday, November 12, 2020 - 9:42:07 AM

### Identifiers

• HAL Id : hal-00468721, version 1

### Citation

Siva Anantharaman, Paliath Narendran, Michael Rusinowitch. Intruders with Caps. Rewriting Techniques and Applications - RTA'07, Jun 2007, Paris, France. pp.20--35. ⟨hal-00468721⟩

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