Paper 2017/042 Original: eprint.iacr.org/2017/042 ↗
Indifferentiability of Iterated Even-Mansour Ciphers with Non-Idealized Key-Schedules: Five Rounds are Necessary and Sufficient
Abstract
We prove that the 5-round iterated Even-Mansour (IEM) construction (which captures the high-level structure of the class of key-alternating ciphers) with a non-idealized key-schedule (such as the trivial key-schedule, where all round keys are equal) is indifferentiable from an ideal cipher. In a separate result, we also prove that five rounds are necessary by describing an attack against the corresponding 4-round construction. This closes the gap regarding the exact number of rounds for which the IEM construction with a non-idealized key-schedule is indifferentiable from an ideal cipher, which was previously only known to lie between four and twelve.
Metadata
- Available format(s)
PDF- Category
- Secret-key cryptography
- Publication info
- Preprint.
- History
- 2017-06-10: last updated
- 2017-01-18: published
- Short URL
- https://ia.cr/2017/042
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2017/042,
author = {Yuanxi Dai and Yannick Seurin and John Steinberger and Aishwarya Thiruvengadam},
title = {Indifferentiability of Iterated Even-Mansour Ciphers with Non-Idealized Key-Schedules: Five Rounds are Necessary and Sufficient},
howpublished = {Cryptology {ePrint} Archive, Paper 2017/042},
year = {2017},
url = {https://eprint.iacr.org/2017/042}
}