Paper 2021/1340
TEDT2 - Highly Secure Leakage-resilient TBC-based Authenticated Encryption
Abstract
Leakage-resilient authenticated encryption (AE) schemes received considerable attention during the previous decade. Two core security models of bounded and unbounded leakage have evolved, where the latter has been motivated in a very detailed and practice-oriented manner. In that setting, designers often build schemes based on (tweakable) block ciphers due to the small state size, such as the recent two-pass AE scheme TEDT from TCHES 1/2020. TEDT is interesting due to its high security guarantees of O(n - log(n^2))-bit integrity under leakage and similar AE security in the black-box setting. Though, a detail limited it to provide only n/2-bit privacy under leakage. In this work, we extend TEDT to TEDT2 in three aspects with the help of a tweakable block cipher with a 3n-bit tweakey: we (1) adopt the idea from the design team of Romulus of replacing TEDT's previous internal hash function with Naito's MDPH, (2) move the nonce from the hash to the tag-generation function both for more efficiency, and (3) strengthen the security of the encryption to obtain beyond-birthday-bound security also under leakage.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. Latincrypt 2021
- DOI
- 10.1007/978-3-030-88238-9_14
- Keywords
- Symmetric-key cryptography authenticated encryption provable security leakage resilience
- Contact author(s)
- elist @ posteo net
- History
- 2022-11-29: revised
- 2021-10-05: received
- See all versions
- Short URL
- https://ia.cr/2021/1340
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2021/1340,
author = {Eik List},
title = {{TEDT2} - Highly Secure Leakage-resilient {TBC}-based Authenticated Encryption},
howpublished = {Cryptology {ePrint} Archive, Paper 2021/1340},
year = {2021},
doi = {10.1007/978-3-030-88238-9_14},
url = {https://eprint.iacr.org/2021/1340}
}
