Paper 2018/391

Tight Adaptively Secure Broadcast Encryption with Short Ciphertexts and Keys

Romain Gay, Lucas Kowalczyk, and Hoeteck Wee

Abstract

We present a new public key broadcast encryption scheme where both the ciphertext and secret keys consist of a constant number of group elements. Our result improves upon the work of Boneh, Gentry, and Waters (Crypto '05) as well as several recent follow-ups (TCC '16-A, Asiacrypt '16) in two ways: (i) we achieve adaptive security instead of selective security, and (ii) our construction relies on the decisional $k$-Linear Assumption in prime-order groups (as opposed to $q$-type assumptions or subgroup decisional assumptions in composite-order groups); our improvements come at the cost of a larger public key. Finally, we show that our scheme achieves adaptive security in the multi-ciphertext setting with a security loss that is independent of the number of challenge ciphertexts.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint. MINOR revision.
Keywords
broadcast encryptionbilinear group
Contact author(s)
luke @ cs columbia edu
History
2018-05-01: received
Short URL
https://ia.cr/2018/391
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2018/391,
      author = {Romain Gay and Lucas Kowalczyk and Hoeteck Wee},
      title = {Tight Adaptively Secure Broadcast Encryption with Short Ciphertexts and Keys},
      howpublished = {Cryptology {ePrint} Archive, Paper 2018/391},
      year = {2018},
      url = {https://eprint.iacr.org/2018/391}
}
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