Sequential Rationality in Cryptographic Protocols

Much of the literature on rational cryptography focuses on analyzing the strategic properties of cryptographic protocols. However, due to the presence of computationallybounded players and the asymptotic nature of cryptographic security, a definition of sequential rationality for this setting has thus far eluded researchers. We propose a new framework for overcoming these obstacles, and provide the first definitions of computational solution concepts that guarantee sequential rationality. We argue that natural computational variants of subgame perfection are too strong for cryptographic protocols. As an alternative, we introduce a weakening called threat-free Nash equilibrium that is more permissive but still eliminates the undesirable "empty threats" of non-sequential solution concepts. To demonstrate the applicability of our framework, we revisit the problem of implementing a mediator for correlated equilibria (Dodis-Halevi-Rabin, Crypto'00), and propose a variant of ...

• Type: Journal
• Year: 2010
• Where: CORR
• Authors: Ronen Gradwohl, Noam Livne, Alon Rosen
• Keywords: CORR 2010, Cryptographic Protocols, Education, Guarantee Sequential Rationality, Sequential Rationality