Template Attack of LWE/LWR-Based Schemes with Cyclic Message Rotation

Area of Science:

• Cryptography
• Computer Security
• Information Theory

Background:

• Lattice-based post-quantum cryptography (PQC) is crucial for future secure communication.
• Side-channel attacks pose a significant threat to PQC implementations.
• Standardization efforts highlight the need for robust security analysis of PQC.

Purpose of the Study:

• To propose a novel message recovery method targeting LWE/LWR-based PQC.
• To enhance the efficiency and success rate of side-channel attacks on PQC.
• To demonstrate the vulnerability of CRYSTAL-Kyber to this attack.

Main Methods:

• Developed a message recovery technique based on leakage in the decapsulation stage.
• Utilized template attacks and cyclic message rotation for ciphertext manipulation.
• Constructed templates using the Hamming weight model for intermediate states.
• Analyzed power leakage during cryptographic operations.

Main Results:

• Successfully recovered secret messages and shared keys from CRYSTAL-Kyber.
• Reduced the number of required power traces for both template creation and attack.
• Significantly increased the attack success rate under low signal-to-noise ratio (SNR).
• Achieved a message recovery success rate of up to 99.6% with sufficient SNR.

Conclusions:

• The proposed method offers a more efficient and effective side-channel attack on lattice-based PQC.
• The findings underscore the importance of considering side-channel vulnerabilities in PQC design.
• Further research is needed to develop countermeasures against such leakage-based attacks.