Key Substitution in the Symbolic Analysis of Cryptographic Protocols (extended version)

Yannick Chevalier (1, 2) , Mounira Kourjieh (3)

1 IRIT-LILaC - Logique, Interaction, Langue et Calcul
2 UT3 - Université Toulouse III - Paul Sabatier
3 IRIT - Institut de recherche en informatique de Toulouse

Key substitution vulnerable signature schemes are signature schemes that permit an intruder, given a public verification key and a signed message, to compute a pair of signature and verification keys such that the message appears to be signed with the new signature key. A digital signature scheme is said to be vulnerable to destructive exclusive ownership property (DEO) If it is computationaly feasible for an intruder, given a public verification key and a pair of message and its valid signature relatively to the given public key, to compute a pair of signature and verification keys and a new message such that the given signature appears to be valid for the new message relatively to the new verification key. In this paper, we prove decidability of the insecurity problem of cryptographic protocols where the signature schemes employed in the concrete realisation have this two properties.

Mots clés: symbolic analysis of cryptographic protocols; signature schemes; insecurity problem; basic narrowing

Domaines: Cryptographie et sécurité [cs.CR]

Yannick Chevalier, Mounira Kourjieh. Key Substitution in the Symbolic Analysis of Cryptographic Protocols (extended version). 2007. ⟨hal-00183337⟩