Paper 2021/1541 Original: eprint.iacr.org/2021/1541 ↗

Revisiting the Security of COMET Authenticated Encryption Scheme

Shay Gueron
Ashwin Jha
Mridul Nandi
Abstract

COMETv1, by Gueron, Jha and Nandi, is a mode of operation for nonce-based authenticated encryption with associated data functionality. It was one of the second round candidates in the ongoing NIST Lightweight Cryptography Standardization Process. In this paper, we study a generalized version of COMETv1, that we call gCOMET, from provable security perspective. First, we present a comprehensive and complete security proof for gCOMET in the ideal cipher model. Second, we view COMET, the underlying mode of operation in COMETv1, as an instantiation of gCOMET, and derive its concrete security bounds. Finally, we propose another instantiation of gCOMET, dubbed COMETv2, and show that this version achieves better security guarantees as well as memory-efficient implementations as compared to COMETv1.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Preprint.
History
2021-11-23: last updated
2021-11-23: published
Short URL
https://ia.cr/2021/1541
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2021/1541,
      author = {Shay Gueron and Ashwin Jha and Mridul Nandi},
      title = {Revisiting the Security of COMET Authenticated Encryption Scheme},
      howpublished = {Cryptology {ePrint} Archive, Paper 2021/1541},
      year = {2021},
      url = {https://eprint.iacr.org/2021/1541}
}
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