Backward-Leak Uni-Directional Updatable Encryption from (Homomorphic) Public Key Encryption

Abstract

The understanding of directionality for updatable encryption (UE) schemes is important, but not yet completed in the literature. We show that security in the backward-leak uni-directional key updates setting is equivalent to the no-directional one. Combining with the work of Jiang (ASIACRYPT 2020) and Nishimaki (PKC 2022), it is showed that the backward-leak notion is the strongest one among all known key update notions and more relevant in practice. We propose two novel generic constructions of UE schemes that are secure in the backward-leak uni-directional key update setting from public key encryption (PKE) schemes: the first one requires a key and message homomorphic PKE scheme and the second one requires a bootstrappable PKE scheme. These PKE can be constructed based on standard assumptions (such as the Decisional Diffie-Hellman and Learning With Errors assumptions).

Available format(s)
Category
Public-key cryptography
Publication info
A minor revision of an IACR publication in PKC 2023
Keywords
Updatable EncryptionBackward-leak Uni-Directional Key UpdateNo-Directional Key UpdateStandard Assumption
Contact author(s)
yao jiang @ ntnu no
History
2023-02-02: last of 3 revisions
See all versions
Short URL
https://ia.cr/2022/324

CC BY

BibTeX

@misc{cryptoeprint:2022/324,
author = {Yao Jiang Galteland and Jiaxin Pan},
title = {Backward-Leak Uni-Directional Updatable Encryption from (Homomorphic) Public Key Encryption},
howpublished = {Cryptology ePrint Archive, Paper 2022/324},
year = {2022},
note = {\url{https://eprint.iacr.org/2022/324}},
url = {https://eprint.iacr.org/2022/324}
}

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