A Novel CCA Attack for NTRU+ KEM

Joohee Lee; Minju Lee; Hansol Ryu; Jaehui Park

Paper 2023/1188

A Novel CCA Attack for NTRU+ KEM

Joohee Lee

, Sungshin Women's University

Minju Lee, Sungshin Women's University

Hansol Ryu, The affiliated institute of ETRI

Jaehui Park, Seoul National University

Abstract

The KpqC competition has begun in 2022, that aims to standardize Post-Quantum Cryptography (PQC) in the Republic of Korea. Among the 16 submissions of the KpqC competition, the lattice-based schemes exhibit the most promising and balanced features in performance. In this paper, we propose an effective classical CCA attack to recover the transmitted session key for NTRU+, one of the lattice-based Key Encapsulation Mechanisms (KEM) proposed in the KpqC competition, for the first time. With the proposed attacks, we show that all the suggested parameters of NTRU+ do not satisfy the claimed security. We also suggest a way to modify the NTRU+ scheme to defend our attack.

Note: Added explanations on some issues with the security proofs of NTRU+

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
Keywords: Post-Quantum Cryptography KpqC Competition Key Encapsulation Mechanism NTRU+
Contact author(s): jooheelee @ sungshin ac kr
20211082 @ sungshin ac kr
hansolryu @ nsr re kr
hiems1855 @ gmail com
History: 2023-12-03: last of 2 revisions; 2023-08-04: received; See all versions
Short URL: https://ia.cr/2023/1188
License: CC0

BibTeX

@misc{cryptoeprint:2023/1188,
      author = {Joohee Lee and Minju Lee and Hansol Ryu and Jaehui Park},
      title = {A Novel CCA Attack for NTRU+ KEM},
      howpublished = {Cryptology ePrint Archive, Paper 2023/1188},
      year = {2023},
      note = {\url{https://eprint.iacr.org/2023/1188}},
      url = {https://eprint.iacr.org/2023/1188}
}