Non-interactive dynamic identity-based broadcast encryption without random oracles

Abstract

A dynamic broadcast encryption (DBE) is a broadcast encryption (BE) scheme where a new user can join the system anytime without modifying preexisting user decryption keys. In this paper, we propose a non-interactive dynamic identity-based broadcast encryption (DIBBE) scheme that is fully secure without random oracles. The PKG does not need to execute any interactive operation with the user during the lifetime of the system. The ciphertext is of constant size, and the public key size is linear in the maximal number of receivers for one encryption. This is the first non-interactive DIBBE scheme which is fully secure without random oracles, and it is collusion resistant for arbitrarily large collusion of users. © 2012 Springer-Verlag.