Paper 2022/855
Tightness Subtleties for Multi-user PKE Notions
, Simula UiB, Simula UiBAbstract
Public key encryption schemes are increasingly being studied concretely, with an emphasis on tight bounds even in a multi-user setting. Here, two types of formalization have emerged, one with a single challenge bit and one with multiple challenge bits. Another modelling choice is whether to allow key corruptions or not. How tightly the various notions relate to each other has hitherto not been studied in detail. We show that in the absence of corruptions, single-bit left-or-right indistinguishability is the preferred notion, as it tightly implies the other (corruption-less) notions. However, in the presence of corruptions, this implication no longer holds; we suggest the use of a more general notion that tightly implies both existing options. Furthermore, for completeness we study how the relationship between left-or-right versus real-or-random evolves in the multi-user PKE setting.
Note: Full version
Metadata
- Available format(s)
-
PDF
- Category
- Public-key cryptography
- Publication info
- Published elsewhere. Minor revision. IMA Coding and Cryptography Conference 2021
- DOI
- 10.1007/978-3-030-92641-0_5
- Keywords
- IndistinguishabilityPublic Key EncryptionMulti-User SecurityAdaptive Corruptions
- Contact author(s)
-
hansh @ simula no
martijn @ simula no - History
- 2023-09-08: last of 2 revisions
- 2022-06-28: received
- See all versions
- Short URL
- https://ia.cr/2022/855
- License
-
CC BY-NC-ND
BibTeX
@misc{cryptoeprint:2022/855,
author = {Hans Heum and Martijn Stam},
title = {Tightness Subtleties for Multi-user PKE Notions},
howpublished = {Cryptology ePrint Archive, Paper 2022/855},
year = {2022},
doi = {10.1007/978-3-030-92641-0_5},
note = {\url{https://eprint.iacr.org/2022/855}},
url = {https://eprint.iacr.org/2022/855}
}
