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Reinventing BrED: A Practical Construction
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| Abstract: | Broadcast Encryption (BE) allows a sender to send an encrypted message to multiple receivers. In a typical broadcast encryption scenario, the broadcaster decides the set of users who can decrypt a particular ciphertext (denoted as the privileged set). Gritti et al. (IJIS'16) introduced a new primitive called Broadcast Encryption with Dealership (BrED), where the dealer decides the privileged set. A BrED scheme allows a dealer to buy content from the broadcaster and sell it to users. It provides better flexibility in managing a large user base. To date, quite a few different constructions of BrED schemes have been proposed by the research community. We find that all existing BrED schemes are insecure under the existing security definitions. We demonstrate a concrete attack on all the existing schemes in the purview of the existing security definition. We also find that the security definitions proposed in the state-of-the-art BrED schemes do not capture the real world. We argue about the inadequacy of existing definitions and propose a new security definition that models the real world more closely. Finally, we propose a new BrED construction and prove it to be secure in our newly proposed security model. |
BibTeX
@article{cic-2024-34858,
title={Reinventing BrED: A Practical Construction},
journal={cic},
publisher={International Association for Cryptologic Research},
volume={1, Issue 3},
url={https://cic.iacr.org//p/1/3/47},
doi={10.62056/ak5txl86bm},
author={Avishek Majumder and Sayantan Mukherjee},
year=2024
}