Welcome to the resource topic for 2020/1099
Title:
Unbounded HIBE with Tight Security
Authors: Roman Langrehr, Jiaxin Pan
Abstract:We propose the first tightly secure and unbounded hierarchical identity-based encryption (HIBE) scheme based on standard assumptions. Our main technical contribution is a novel proof strategy that allows us to tightly randomize user secret keys for identities with arbitrary hierarchy depths using low entropy hidden in a small and hierarchy-independent master public key. The notion of unbounded HIBE is proposed by Lewko and Waters (Eurocrypt 2011). In contrast to most HIBE schemes, an unbounded scheme does not require any maximum depth to be specified in the setup phase, and user secret keys or ciphertexts can be generated for identities of arbitrary depths with hierarchy-independent system parameters. While all the previous unbounded HIBE schemes have security loss that grows at least linearly in the number of user secret key queries, the security loss of our scheme is only dependent on the security parameter, even in the multi-challenge setting, where an adversary can ask for multiple challenge ciphertexts. We prove the adaptive security of our scheme based on the Matrix Decisional Diffie-Hellman assumption in prime-order pairing groups, which generalizes a family of standard Diffie-Hellman assumptions such as k-Linear.
ePrint: https://eprint.iacr.org/2020/1099
Talk: https://www.youtube.com/watch?v=o3wes8g5spk
Slides: https://iacr.org/submit/files/slides/2020/asiacrypt/ac2020/313/slides.pdf
See all topics related to this paper.
Feel free to post resources that are related to this paper below.
Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.
For more information, see the rules for Resource Topics .