Security Evaluation on KpqC Round 1 Lattice-Based Algorithms Using Lattice Estimator

Post-quantum cryptography is expected to become one of the fundamental technologies in the field of security that requires public-key cryptosystems, potentially replacing standards such as RSA and ECC, as it is designed to withstand attacks using quantum computers. In South Korea, there is an ongoing standardization effort called the KpqC (Korean Post-Quantum Cryptography) competition for developing post-quantum cryptography as a national standard. The competition is in its first round, and it has introduced a total of 16 candidate algorithms for evaluation. In this paper, we analyze the security of five algorithms among the eight lattice-based schemes in the first round of the KpqC competition. We assess their security using M. Albrecht’s Lattice Estimator, focusing on problems related to LWE (Learning with Errors) and LWR (Learning with Rounding). Additionally, we compare the security analysis results with the claims in the proposal documents for each algorithm. When an algorithm fails to achieve the level of security in its proposal, we suggest potential types of attacks that need to be considered for further analysis and improvement.