Work

Breaking Enhanced CBC and Its Application

Year: 2025

Type: article

Abstract: The Enhanced Cipher Block Chaining scheme (eCBC) is an authentication encryption scheme (AE) improved from the CBC encryption scheme. It is shown that eCBC scheme fails to achieve ciphertext integrity (INT-CTXT): the IV is unauthenticated and the tag is a linear XOR of ciphertext hashes, enabling trivial forgeries such as IV substitution, block cancellation, and permutation. Furthermore, the medical image application diagonal block encryption based on eCBC scheme is also insecure. Its deterministic design leaks structural information, breaking confidentiality (IND-CPA). At the same time, it also inherits the forgery weaknesses of eCBC scheme, breaking authenticity. The results highlight that neither eCBC scheme nor its application meet AE security goals. And it is recommended to use standardized AE schemes such as SIV, GCM, or Ascon instead of ad hoc designs.

Source: Mathematics

DOI: 10.3390/math13223595

Authors: Shuping Mao, Peng Wang, Yan Jia, Gang Liu, Ying Chen

Institutions: Beijing Electronic Science and Technology Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Institute of Information Engineering

Language: English

Topic: Cryptographic Implementations and Security

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,137

Funder: Fundamental Research Funds for the Central Universities