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when quoting this document, please refer to the following
URN: urn:nbn:de:0030-drops-6911
URL: http://drops.dagstuhl.de/opus/volltexte/2006/691/
Zalinescu, Eugen ; Cortier, Véronique ; Rusinowitch, Michaël

Relating two standard notions of secrecy

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Abstract

Two styles of definitions are usually considered to express that a security protocol preserves the confidentiality of a data { t s}. Reach-ability-based secrecy means that { t s} should never be disclosed while equi-valence-based secrecy states that two executions of a protocol with distinct instances for { t s} should be indistinguishable to an attacker. Although the second formulation ensures a higher level of security and is closer to cryptographic notions of secrecy, decidability results and automatic tools have mainly focused on the first definition so far. This paper initiates a systematic investigation of situations where syntactic secrecy entails strong secrecy. We show that in the passive case, reachability-based secrecy actually implies equivalence-based secrecy for signatures, symmetric and asymmetric encryption provided that the primitives are probabilistic. For active adversaries in the case of symmetric encryption, we provide sufficient (and rather tight) conditions on the protocol for this implication to hold.

BibTeX - Entry

@InProceedings{zalinescu_et_al:DSP:2006:691,
  author =	{Eugen Zalinescu and V{\'e}ronique Cortier and Michaël Rusinowitch},
  title =	{Relating two standard notions of secrecy},
  booktitle =	{Workshop "Trustworthy Software" 2006 },
  year =	{2006},
  editor =	{Serge Autexier and Stephan Merz and Leon van der Torre and Reinhard Wilhelm and Pierre Wolper},
  publisher =	{Internationales Begegnungs- und Forschungszentrum f{"u}r Informatik (IBFI), Schloss Dagstuhl, Germany},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2006/691},
  annote =	{Keywords: Verification, security protocols, secrecy, applied-pi calculus},
  ISBN =	{978-3-939897-02-6}
}

Keywords: Verification, security protocols, secrecy, applied-pi calculus
Seminar: Workshop "Trustworthy Software" 2006
Documenttype: InProceedings
Issue date: 2006
Date of publication: 26.09.2006

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