Cryptanalysis of hybrid cryptosystems

Gilles Millérioux (1)

1 CRAN - Centre de Recherche en Automatique de Nancy

An essential issue for the validation of ciphers is the cryptanalysis, that is the study of attacks in order to reveal possible weaknesses. In this paper, we propose a systematic and unified methodology for cryptanalyzing known chaos-based cryptosystems borrowed from the open literature, namely shift keying, discrete parameter modulation, switched message-embedding, time-varying delay-based schemes. It is shown that all of them have a hybrid feature. Based on this consideration, the cryptanalysis amounts to perform a specific parameter identification. The method is extended in straighforwad way for hybrid cryptosystems defined over finite fields, involving in particular Boolean functions. The complexity of the cryptanalysis is derived regardless of the exhibited dynamics and provides a new quantitative measure for security assessment. That allows to show by the way that most of the chaos-based cryptosystems proposed so far in the literature are weak.

Mots clés: Cryptanalysis; chaotic systems; hybrid systems

Domaines: Optimisation et contrôle [math.OC]

Gilles Millérioux. Cryptanalysis of hybrid cryptosystems. International journal of bifurcation and chaos in applied sciences and engineering , 2013, 23 (10), pp.1350173-1-1350173-13. ⟨10.1142/S0218127413501733⟩. ⟨hal-00905314⟩