Work

CCA-attacks on lattice-based encryption-decryption schemes

Year: 2025

Type: article

Abstract: This paper presents two distinct chosen-ciphertext attacks (CCA) against lattice-based encryption and decryption schemes, in particular based on the LWE problem, a class of post-quantum cryptographic algorithms. First we attack fully homomorphic encryption-decryption schemes (FHE) exploiting the additional information that the small modulus reduction offers. We compare this attack with the $$CPA^D$$ attack presented in Checri (2024). Afterwards we present an attack against Kyber.CPAPKE, and another against a weakened version of Kyber.KEM where the cyphertext is not checked for correctness; and compare them to the previous Key Mismatch Attack in Qin (2021). Our work remarks the importance of protecting the decryption function in the different implementations of these cryptographic schemes, and the importance of CCA security in nowadays cryptosystems.

Source: Cryptography and Communications

DOI: 10.1007/s12095-025-00837-z

Authors: Alba Hernández Costoya, Alba Larraya Sancho, Miguel Ángel Marco Buzunáriz

Institutions: University of the Basque Country, Basque Center for Applied Mathematics, Universidad de Zaragoza

Language: English

Topic: Cryptography and Data Security

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,190

Funder: Ministerio de Ciencia, Innovación y Universidades