Paper 2026/896
CORAL Faster Isogeny Group Action for Post-Quantum NIKE
, IBM Research - Zurich, IBM Research - Zurich, Technical University of Munich, IBM Research - Zurich, ETH ZurichAbstract
There are two kinds of cryptographic group actions: restricted and unrestricted. While unrestricted actions like (qt-)PEGASIS are needed for more advanced constructions, restricted ones like dCTIDH are sufficient for instantiating a NIKE and usually much more efficient. In this work, we propose CORAL, a significantly faster algorithm to evaluate the same action as (qt-)PEGASIS, but in a restricted fashion; CORAL only computes two-dimensional $2$-isogenies to evaluate the action and outperforms both recent unrestricted (KLaPoTi, (qt-)PEGASIS) and (restricted) CSIDH-based approaches (SQALE, dCTIDH). In essence, CORAL trades off unrestrictedness for efficiency. Our unoptimised C implementation evaluates a group-action in 240 ms with a 2032-bit prime. When used to construct a non-interactive key exchange, CORAL yields an actively secure post-quantum NIKE with compact public keys (e.g. 256 bytes for 2032-bit primes).
Metadata
- Available format(s)
-
PDF
- Category
- Public-key cryptography
- Publication info
- A minor revision of an IACR publication in CRYPTO 2026
- Keywords
- NIKEGroup ActionsIsogenies
- Contact author(s)
-
andrea basso @ ibm com
coral @ gbor in
ryan @ rueg re
sschaeffle @ ethz ch - History
- 2026-05-10: approved
- 2026-05-07: received
- See all versions
- Short URL
- https://ia.cr/2026/896
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2026/896,
author = {Andrea Basso and Giacomo Borin and Ryan Rueger and Sina Schaeffler},
title = {{CORAL} Faster Isogeny Group Action for Post-Quantum {NIKE}},
howpublished = {Cryptology {ePrint} Archive, Paper 2026/896},
year = {2026},
url = {https://eprint.iacr.org/2026/896}
}
