Multivariate public key cryptosystems from diophantine equations

Abstract

Wang et al. introduced in (A medium-field multivariate public-key encryption scheme. Topics in Cryptology--CTRSA 2006: The Cryptographers' Track at the RSA Conference, 2006) a multivariate public key cryptosystem, called MFE cryptosystem, and it is appealing as it is based on a simple polynomial identity. Their system, however, was subsequently broken by Ding et al. in (High order linearization equation (hole) attack on multivariate public key cryptosystems. Public key cryptography--PKC 2007: 10th international conference on practice and theory in public-key cryptography, 2007a, ?-Invertible cycles for multivariate quadratic public key cryptography. Public key cryptography--PKC 2007: 10th international conference on practice and theory in public-key cryptography, 2007b). Inspired by their work, we present a more general framework for multivariate public key cryptosystems, which combines ideas from both triangular and oil-vinegar schemes. Within this framework, we propose a new public key cryptosystem based on a solution of a Diophantine equation over polynomial rings.