Paper 2007/201 Original: eprint.iacr.org/2007/201 ↗
The BBG HIBE Has Limited Delegation
Abstract
At Eurocrypt 2005, Boneh, Boyen, and Goh presented a hierarchical IBE for which they claimed a novel property, called limited delegation: it is possible to give an entity a private key that restricts it from generating descendant private keys beyond some depth d; in particular, with d equal to the entity's depth, such a key allows decryption only. In this paper, we argue that this claim is nonobvious and requires proof, provide a precise model for arguing about limited delegation, and prove that the Boneh-Boyen-Goh system does, in fact, have limited delegation. Whereas Boneh, Boyen, and Goh prove their system semantically secure under the BDHI assumption, our proof of limited delegation requires the stronger BDHE assumption.
Metadata
- Available format(s)
PDF- Category
- Public-key cryptography
- Publication info
- Preprint.
- History
- 2007-05-31: last updated
- 2007-05-31: published
- Short URL
- https://ia.cr/2007/201
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2007/201,
author = {Hovav Shacham},
title = {The BBG HIBE Has Limited Delegation},
howpublished = {Cryptology {ePrint} Archive, Paper 2007/201},
year = {2007},
url = {https://eprint.iacr.org/2007/201}
}