CSP-DHIES: a new public-key encryption scheme from matrix conjugation

We propose a new public-key cryptosystem named conjugacy search problem-based Diffie–Hellman integrated encryption scheme (CSP-DHIES), by using conjugation-related assumptions for a special monoid of matrices of truncated multi-variable polynomials over the ring Z12 where the CSP is assumed to be intractable. Our construction can be viewed as the first noncommunicative variant of the well-known DHIES cryptosystem. Under the assumptions of the intractability of the CSP-based hash Diffie–Hellman problem and the CSP-based oracle Diffie–Hellman problem, our scheme is provably secure against both chosenplaintext attacks and secure against chosen-ciphertext attacks. Our proofs are constructed in the standard model. We also discuss the possibility of implementing our proposal using braid groups. Copyright © 2011 John Wiley & Sons, Ltd.