Vérification des protocoles cryptographiques et propriétés algébriques

Stéphanie Delaune. Vérification des protocoles cryptographiques et propriétés algébriques. Ph.D. Thesis, Laboratoire Spécification et Vérification, ENS Cachan, France, 2006.

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Abstract

Cryptographic protocols are small concurrent programs designed to guarantee the security of exchanges between participants using non-secure medium. Establishing the correctness of these protocols is crucial given the increasing number of applications, such as electronic commerce, that exchange information on the Internet. Unfortunately, the existence of cryptographic primitives such as encryption is not sufficient to ensure security. The security of exchanges is ensured by cryptographic protocols which are notoriously error-prone.
The formal verification of cryptographic protocols is a difficult problem that can be seen as a particular model-checking problem in an hostile environment. To verify such protocols, a line of research consists in considering encryption as a black box and assuming that an adversary can't learn anything from an encrypted message except if he has the key. This is called the perfect cryptography assumption. Many results have been obtained under this assumption, but such an assumption is too strong in general. Some attacks exploit in a clever way the interaction between protocol rules and properties of cryptographic operators.
In this thesis, we relax the perfect cryptography assumption by taking into account some algebraic properties of cryptographic primitives. We give decision procedures for the security problem in presence of several algebraic operators.

BibTeX

@phdthesis{THESE-delaune06,
  abstract =      {Cryptographic protocols are small concurrent programs
                   designed to guarantee the security of exchanges
                   between participants using non-secure medium.
                   Establishing the correctness of these protocols is
                   crucial given the increasing number of applications,
                   such as electronic commerce, that exchange
                   information on the Internet. Unfortunately, the
                   existence of cryptographic primitives such as
                   encryption is not sufficient to ensure security. The
                   security of exchanges is ensured by cryptographic
                   protocols which are notoriously error-prone.\par The
                   formal verification of cryptographic protocols is a
                   difficult problem that can be seen as a particular
                   model-checking problem in an hostile environment. To
                   verify such protocols, a line of research consists in
                   considering encryption as a black box and assuming
                   that an adversary can't learn anything from an
                   encrypted message except if he has the key. This is
                   called the \emph{perfect cryptography} assumption.
                   Many results have been obtained under this
                   assumption, but such an assumption is too strong in
                   general. Some attacks exploit in a clever way the
                   interaction between protocol rules and properties of
                   cryptographic operators. \par In this thesis, we
                   relax the perfect cryptography assumption by taking
                   into account some algebraic properties of
                   cryptographic primitives. We give decision procedures
                   for the security problem in presence of several
                   algebraic operators.},
  author =        {Delaune, St{\'e}phanie},
  month =         jun,
  school =        {Laboratoire Sp{\'e}cification et V{\'e}rification,
                   ENS Cachan, France},
  type =          {Th{\`e}se de doctorat},
  title =         {V{\'e}rification des protocoles cryptographiques et
                   propri{\'e}t{\'e}s alg{\'e}briques},
  year =          {2006},
  nmonth =        {6},
  lsv-category =  {thes},
  wwwpublic =     {public and ccsb},
}