Adaptively Secure Broadcast Encryption With Short Ciphertexts
The authors propose an adaptively secure broadcast encryption scheme with short ciphertexts, where the size of broadcast encryption message is fixed regardless of the size of the broadcast group. In their proposed scheme, members can join and leave the group without requiring any change to public parameters of the system or private keys of existing members. Their construction has a twofold improvement over previously known best broadcast encryption schemes. First, they propose a scheme that immediately yields adaptive security without any increase in the size of ciphertexts or use of a random oracle. Secondly, the proof of security in the proposed scheme is defined in a stronger security model closely simulating an adversary in real world.