Section: New Results

Verification of Security Protocols in the Computational model

Participant : Bruno Blanchet.

Bruno Blanchet implemented several extensions of his computational protocol verifier CryptoVerif. In particular, he improved the global dependency analysis, used in order to show that the result of all tests is independent from some random values. He improved the proof of secrecy properties, in particular to prove forward secrecy properties. He also improved the merging of branches of tests, in particular to be able to merge the two branches of if $b$ then $P_1$ else $P_2$ even when variables are renamed between $P_1$ and $P_2$. Finally, he added the display of an explanation of why a cryptographic transformation fails, to make the tool easier to use. The extended tool is available at http://cryptoverif.inria.fr .

Within the ANR project AnaStaSec, Bruno Blanchet verified an air-ground avionic security protocol (International Civil Aviation Organization (ICAO) Document 9880: Manual on Detailed Technical Specifications for the Aeronautical Telecommunication Network (ATN) using ISO/OSI standards and protocols, Part IV) using CryptoVerif. He proved entity authentication and message authenticity for the main protocol, in the computational model of cryptography, and made comments on some points that should be clarified in the protocol specification. He presented this work at a meeting of the secure dialog service working group of ICAO, in Toulouse, September 2015. The working group was strongly interested by the presentation and welcomed the proposal to apply these modelling and formal verification techniques as part of its validation activities.