Paper 2021/648
Security of COFB against Chosen Ciphertext Attacks
Mustafa Khairallah
Abstract
COFB is a lightweight Authenticated Encryption with Associated Data (AEAD) mode based on block ciphers.
It was proposed in CHES 2017 and is the basis for GIFT-COFB, a finalist in the NIST lightweight standardization project.
It comes with provable security results that guarantee its security up to the birthday
bound in the nonce-respecting model. However, the designers offer multiple versions of the analysis with different details and the implications of attacks against the scheme are not discussed deeply. In this article, we look at a group of possible forgery and privacy attacks against COFB. We show that the security for both forgery and privacy is bounded by the number of forgery attempts. We show the existence of forgery and privacy attacks with success probability
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Published by the IACR in FSE 2022
- Keywords
- AEADGIFTCOFBForgeryConfidentialityAuthenticationAuthenticated Encryption
- Contact author(s)
- mustafa khairallah @ ntu edu sg
- History
- 2022-02-22: last of 7 revisions
- 2021-05-20: received
- See all versions
- Short URL
- https://ia.cr/2021/648
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2021/648, author = {Mustafa Khairallah}, title = {Security of {COFB} against Chosen Ciphertext Attacks}, howpublished = {Cryptology {ePrint} Archive, Paper 2021/648}, year = {2021}, url = {https://eprint.iacr.org/2021/648} }