A Proposal for Efficient Multiplication and Inverse Calculation in Streamlined NTRU Prime

With the development of quantum computers, widely used cryptosystems will be able broken in the near future. Therefore, researches on Post-Quantum Cryptography (PQC) has been actively conducted. In this paper, a method to improve the calculation of Streamlined NTRU Prime, which is one of the PQC. The authors propose to employ the Cyclic Vector Multiplication Algorithm (CVMA), which uses a nomal basis called Type-II Optimal Normal Basis, with the parameters of Streamlined NTRU Prime. The processing speed of multiplication and inversion are compared with those of previous studies. As a result, the multiplication by the CVMA was 58% faster than the previous method with a certain condition. On the other hand, the inverse calculation was 50 times slower than the previous method due to the lack of optimizations.