International Association for Cryptologic Research (IACR)
Abstract
Very recently, a key exchange scheme called HK17 was submitted to NIST as a candidate of the standard of post-quantum cryptography. The HK17 scheme employs some hypercomplex numbers as the basic objects, such as quaternions and octonions. In this paper, we show that HK17 is insecure since a passive adversary can recover the shared key in polynomial time