Modeling Cryptographic Properties of Voice and Voice-Based Entity Authentication

Strong and/or multi-factor entity authentication protocols are of crucial importance in building successful identity management architectures. Popular mechanisms to achieve these types of entity authentication are biometrics, and, in particular, voice, for which there are especially interesting business cases in the telecommunication and financial industries, among others. Despite several studies on the suitability of voice within entity authentication protocols, there has been little or no formal analysis of any such methods. In this paper we embark into formal modeling of seemingly cryptographic properties of voice. The goal is to define a formal abstraction for voice, in terms of algorithms with certain properties, that are of both combinatorial and cryptographic type. While we certainly do not expect to achieve the perfect mathematical model for a human phenomenon, we do hope that capturing some properties of voice in a formal model would help towards the design and analysis of voice-based cryptographic protocols, as for entity authentication. In particular, in this model we design and formally analyze two voice-based entity authentication schemes, the first being a voice-based analogue of the conventional password-transmission entity authentication scheme. We also design and analyze, in the recently introduced bonded-retrieval model [4], one voice-and-password-based entity authentication scheme that is additionally secure against intrusions and brute-force attacks, including dictionary attacks.