Constant Size Ciphertext HIBE in the Augmented Selective-ID Model and its Extensions

Sanjit Chatterjee; Palash Sarkar

Paper 2007/084

Constant Size Ciphertext HIBE in the Augmented Selective-ID Model and its Extensions

Sanjit Chatterjee and Palash Sarkar

Abstract

At Eurocrypt 2005, Boneh, Boyen and Goh presented a constant size ciphertext hierarchical identity based encryption (HIBE) protocol. Our main contribution is to present a variant of the BBG-HIBE. The new HIBE is proved to be secure (without any degradation) in an extension of the sID model (denoted the s$^+$-ID model) and the components of the identities are from $\bbbz_p$, where $p$ is a suitable large prime. The BBG-HIBE is proved to be secure in the selective-ID (sID) security model and the components of the identities are from $\bbbz_p^*$. In the s$^+$-ID model the adversary is allowed to vary the length of the challenge identity whereas this is not allowed in the sID model. The new HIBE shares all the good features of the BBG-HIBE. The drawback is that the public parameters and the private key are longer than that of the BBG-HIBE. We also provide two more extensions of the basic constant size ciphertext HIBE. The first is a constant size ciphertext HIBE secure in the generalised selective-ID model $\clsM_2$. The second one is a product construction composed of two HIBEs and a trade-off is possible between the private key size and the ciphertext size.

Metadata

Available format(s): PDF PS
Category: Cryptographic protocols
Publication info: Published elsewhere. Unknown where it was published
Contact author(s): sanjit_t @ isical ac in
History: 2007-03-05: received
Short URL: https://ia.cr/2007/084
License: CC BY

BibTeX

@misc{cryptoeprint:2007/084,
      author = {Sanjit Chatterjee and Palash Sarkar},
      title = {Constant Size Ciphertext {HIBE} in the Augmented Selective-{ID} Model and its Extensions},
      howpublished = {Cryptology {ePrint} Archive, Paper 2007/084},
      year = {2007},
      url = {https://eprint.iacr.org/2007/084}
}