Paper 2016/516

Boneh-Gentry-Hamburg's Identity-based Encryption Schemes Revisited

Ferucio Laurentiu Tiplea and George Teseleanu and Sorin Iftene and Anca-Maria Nica

Abstract

We revise Boneh-Gentry-Hamburg's identity-based encryption schemes and we show that we can renounce to the use of pseudo-random functions. We then prove IND-ID-CPA and ANON-IND-ID-CPA security of these schemes by showing that the advantage of any efficient adversary against these schemes is less than or equal to the quadratic residuosity advantage of some efficient adversary against the RSA generator. This greatly improves the existing upper bounds (being probably the tightest upper bound).