Paper 2020/622
The Direction of Updatable Encryption does not Matter Much
Yao Jiang
Abstract
Updatable encryption schemes allow for key rotation on ciphertexts. A client outsourcing storage of encrypted data to a cloud server can change its encryption key. The cloud server can update the stored ciphertexts to the new key using only a token provided by the client. This paper solves two open problems in updatable encryption, that of uni-directional vs. bi-directional updates, and post-quantum security. The main result in this paper is to analyze the security notions based on uni- and bi-directional updates. Surprisingly, we prove that uni- and bi-directional variants of each security notion are equivalent. The second result in this paper is to provide a new and efficient updatable encryption scheme based on the Decisional Learning with Error assumption. This gives us post-quantum security. Our scheme is bi-directional, but because of our main result, this is sufficient.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- A minor revision of an IACR publication in ASIACRYPT 2020
- DOI
- 10.1007/978-3-030-64840-4_18
- Keywords
- updatable encryptioncloud storagekey rotationlattice-based cryptographypost-quantum cryptography
- Contact author(s)
- yao jiang @ ntnu no
- History
- 2021-06-20: last of 3 revisions
- 2020-05-28: received
- See all versions
- Short URL
- https://ia.cr/2020/622
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2020/622,
author = {Yao Jiang},
title = {The Direction of Updatable Encryption does not Matter Much},
howpublished = {Cryptology ePrint Archive, Paper 2020/622},
year = {2020},
doi = {10.1007/978-3-030-64840-4_18},
note = {\url{https://eprint.iacr.org/2020/622}},
url = {https://eprint.iacr.org/2020/622}
}
