On the Post-Quantum Security of Classical Authenticated Encryption Schemes

Nathalie Lang; Stefan Lucks

Paper 2023/218

On the Post-Quantum Security of Classical Authenticated Encryption Schemes

Nathalie Lang

, Bauhaus University, Weimar

Stefan Lucks

, Bauhaus University, Weimar

Abstract

We study the post-quantum security of authenticated encryption (AE) schemes, designed with classical security in mind. Under superposition attacks, many CBC-MAC variants have been broken, and AE modes employing those variants, such as EAX and GCM, thus fail at authenticity. As we show, the same modes are IND-qCPA insecure, i.e., they fail to provide privacy under superposition attacks. However, a constrained version of GCM is IND-qCPA secure, and a nonce-based variant of the CBC-MAC is secure under superposition queries. Further, the combination of classical authenticity and classical chosen-plaintext privacy thwarts attacks with superposition chosen-ciphertext and classical chosen-plaintext queries -a security notion that we refer to as IND-qdCCA. And nonce-based key derivation allows generically turning an IND-qdCCA secure scheme into an IND-qCCA secure scheme.

Metadata

Available format(s): PDF
Category: Attacks and cryptanalysis
Publication info: Published elsewhere. AfricaCrypt 2023
Keywords: authenticated encryption post-quantum security
Contact author(s): nathalie lang @ uni-weimar de
stefan lucks @ uni-weimar de
History: 2023-06-16: last of 2 revisions; 2023-02-17: received; See all versions
Short URL: https://ia.cr/2023/218
License: CC BY

BibTeX

@misc{cryptoeprint:2023/218,
      author = {Nathalie Lang and Stefan Lucks},
      title = {On the Post-Quantum Security of Classical Authenticated Encryption Schemes},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/218},
      year = {2023},
      url = {https://eprint.iacr.org/2023/218}
}