Paper 2022/152

K-XMSS and K-SPHINCS$^+$:Hash based Signatures with\\Korean Cryptography Algorithms

Minjoo Sim, Siwoo Eum, Gyeongju Song, HyeokDong Kwon, Kyungbae Jang, HyunJun Kim, HyunJi Kim, Yujin Yang, Wonwoong Kim, Wai-Kong Lee, and Hwajeong Seo

Abstract

Hash-Based Signature (HBS) uses a hash function to construct a digital signature scheme, where its security is guaranteed by the collision resistance of the hash function used. To provide sufficient security in the post-quantum environment, the length of hash should be satisfied. Modern HBS can be classified into stateful and stateless schemes. Two representative stateful and stateless HBS are XMSS and SPHINCS$^+$, respectively. In this paper, we propose two HBS schemes: K-XMSS and K-SPHINCS$^+$, which replace internal hash functions of XMSS and SPHINCS$^+$ with Korean cryptography algorithms. K-XMSS is a stateful signature, while K-SPHINCS$^+$ is its stateless counterpart. We also showcase the reference implementation of K-XMSS and K-SPHINCS$^+$ employing LSH and two hash functions based on block ciphers (i.e. CHAM and LEA) as the internal hash function. The reference code is developed as a proof-of-concept, which can be optimized for better performance using advanced implementation techniques (e.g. AVX2 and NEON).