Similar Keys of Multivariate Quadratic Public Key Cryptosystems

摘要

Most multivariate schemes have potentially much higher performance than other public key cryptosystems. Wolf and Preneel show multivariate quadratic public key schemes have many equivalent keys and provide some transformations to identify the keys. In this paper, we propose the idea of similar keys of MQ-based public key cryptosystems(PKCs) and provide a method to reduce the size of private key in MQ-based PKCs to 50% ～70% of its original size. And our method is generic for most MQ-based PKCs except for UOV-like and STS-like schemes. Moreover, our method remains the equivalent security and efficiency with original MQ-based PKCs.