TY - GEN A1 - Sheikhi‐Garjan, Maryam A1 - Orhon Kılıç, N. Gamze A1 - Cenk, Murat T1 - Supersingular Isogeny-based Ring Signature T2 - International Journal of Information Security Science N2 - The increasing demand for secure and anonymous transactions raises the popularity of ring signatures, which is a digital signature scheme that allows identifying a group of possible signers without revealing the identity of the actual signer. This paper presents efficient supersingular isogeny-based ring signature and linkable ring signature schemes that will find potential applications in post-quantum technologies. We develop the ring signature scheme by applying the Fiat-Shamir transform on the sigma protocol for a ring which we obtain from the supersingular isogeny-based interactive zero-knowledge identification scheme by adopting the scheme for a ring. We also extend our ring signature protocol with an additional parameter, i.e., a tag that provides to detect if a signer issues two signatures concerning the same ring by preserving anonymity and linkable anonymity. The signature size of our ring signature protocols increases logarithmically in the size of the ring thanks to the Merkle trees. We show the security proofs and efficiency analyses of the protocols offered. Moreover, we provide the implementation results of the supersingular isogeny-based ring signature, which offers small signature sizes for NIST post-quantum security levels. Y1 - 2023 U6 - https://doi.org/10.55859/ijiss.1187756 SN - 2147-0030 VL - 12 IS - 1 SP - 32 EP - 57 PB - Seref Sagiroglu ER - TY - GEN A1 - Yaman Gökce, Neslihan A1 - Gökce, Anıl Burak A1 - Cenk, Murat T1 - A fast NTRU software implementation based on 5-way TMVP T2 - Journal of Information Security and Applications N2 - The fast and efficient operation of post-quantum cryptographic algorithms has become an important research topic, especially with the recent developments and the process of the PQC Standardization Project by NIST. Various algorithms based on lattices are chosen to be finalists in this project. Number Theoretic Transform (NTT), Toom–Cook, Karatsuba, and Toeplitz matrix–vector product (TMVP) are considered in order to efficiently perform multiplications in quotient polynomial rings required by the cryptographic schemes based on lattices. In this paper, we propose a 5-way split TMVP-based algorithm for multiplication in polynomial quotient rings and determine its computational complexity. The new algorithm is derived from a 5-term polynomial multiplication algorithm using 13 multiplications with coefficients of only 1 or -1 that provide efficiency. We also implement it for all parameter sets of NTRU. The results show that we have up to 34%, 35%, and 157% speed-up against Toom4-Karatsuba implementation in key generation, encapsulation, and decapsulation, respectively. KW - Post-quantum cryptography KW - Lattice-based cryptography KW - Toeplitz matrices KW - NTRU KW - TMVP KW - Polynomial multiplication Y1 - 2024 U6 - https://doi.org/10.1016/j.jisa.2023.103688 SN - 2214-2126 VL - 81 PB - Elsevier BV ER -