QCB is Blindly Unforgeable

Jannis Leuther; Stefan Lucks

Paper 2023/1653 Original: eprint.iacr.org/2023/1653 ↗

QCB is Blindly Unforgeable

Jannis Leuther

Stefan Lucks

Abstract

QCB is a proposal for a post-quantum secure, rate-one authenticated encryption with associated data scheme (AEAD) based on classical OCB3 and \(\Theta\)CB, which are vulnerable against a quantum adversary in the Q2 setting. The authors of QCB prove integrity under plus-one unforgeability, whereas the proof of the stronger definition of blind unforgeability has been left as an open problem. After a short overview of QCB and the current state of security definitions for authentication, this work proves blind unforgeability of QCB. Finally, the strategy of using tweakable block ciphers in authenticated encryption is generalised to a generic blindly unforgeable AEAD model.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint.
History: 2023-12-08: last updated; 2023-10-25: published
Short URL: https://ia.cr/2023/1653
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2023/1653,
      author = {Jannis Leuther and Stefan Lucks},
      title = {QCB is Blindly Unforgeable},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1653},
      year = {2023},
      url = {https://eprint.iacr.org/2023/1653}
}