A Novel Power Analysis Attack against CRYSTALS-Dilithium Implementation

Post-Quantum Cryptography (PQC) was proposed due to the potential threats quantum computer attacks against conventional public key cryptosystems, and four PQC algorithms besides CRYSTALS-Dilithium (Dilithium for short) have so far been selected for National Institute of Standards and Technology (NIST) standardization. However, the selected algorithms are still vulnerable to side-channel attacks in practice, and their physical security need to be further evaluated. This paper proposes two efficient power analysis attacks against Dilithium implementation, the optimized fast two-stage approach and the single-bit approach, aiming at reducing the key guess space. Our findings reveal that the optimized approach outperforms the conservative approach and the fast two-stage approach proposed in ICCD 2021 by factors of 338 and 49, respectively. Similarly, compared to these two approaches, the single-bit approach achieves acceleration of 367 times and 53 times, respectively.