BGN authentication and its extension to convey message commitments

Abstract

We instantiate the cryptosystem proposed by Boneh, Goh, and Nissim in TCC'05 [5] into an entity authentication scheme, in which an entity is authenticated by an interactive zero-knowledge proof on its private key. Completeness and soundness of our scheme is supported by the indistinguishability of BGN ciphertexts of sums and products, which essentially relies on the semantic security of the BGN cryptosystem. We further extend our scheme so that the authentication conveys Pedersen commitments on a message, while the BGN authentication serves the 'proving you know how to open' functionality for the commitment. Our message commitment scheme is both statistically hiding and computationally binding provided the subgroup decision problem is hard. © Springer-Verlag Berlin Heidelberg 2006.