Formal Analysis of E-Cash Protocols

Jannik Dreier (1) , Ali Kassem (2) , Pascal Lafourcade (3)

1 CASSIS - Combination of approaches to the security of infinite states systems
2 VERIMAG - IMAG - VERIMAG
3 LIMOS - Laboratoire d'Informatique, de Modélisation et d'optimisation des Systèmes

Electronic cash (e-cash) aims at achieving client privacy at payment, similar to real cash. Several security protocols have been proposed to ensure privacy in e-cash, as well as the necessary unforgery properties. In this paper, we propose a formal framework to define, analyze, and verify security properties of e-cash systems. To this end, we model e-cash systems in the applied π-calculus, and we define two client privacy properties and three properties to prevent forgery. Finally, we apply our definitions to an e-cash protocol from the literature proposed by Chaum et al., which has two variants and a real implementation based on it. Using ProVerif, we demonstrate that our framework is suitable for an automated analysis of this protocol.

Mots clés: E-Cash; Formal Analysis; Double Spending; Exculpability; Privacy; Applied π-Calculus; ProVerif

Domaines: Cryptographie et sécurité [cs.CR]

Jannik Dreier, Ali Kassem, Pascal Lafourcade. Formal Analysis of E-Cash Protocols. 12th International Conference on Security and Cryptography (SECRYPT 2015), Jul 2015, Colmar, France. ⟨10.5220/0005544500650075⟩. ⟨hal-01337410⟩