Matrix extensions of the rsa algorithm.

[Timothy Newsham <newsham@wiliki.eng.hawaii.edu>]

I have posted this before and never saw any reply.
The following sounded appealing to me because it gives
public key features with private key cryptosystem speeds.

Matrix Extensions of the RSA Algorithm
Chih-Chwen Chuang and James George Dunham
CRYPTO '90

Abstract

A new matrix extension of the RSA algorithm is proposed which is based
on the Cayley-Hamilton theorem and a one-way function.  The security
of this algorithm rests on that of the RSA algorithm and the one-way
function.  The computational efficiency of the new algorithm depends
on the dimension of the marix.  The most efficient implementation is
the 2x2 case in which both the encryption and decryption use a single
modulo arithmetic multiplication and single evaluation of the one-way
function.


later in the paper..

'Under a chosen plaintext attack on the key, the security of the new
algorithm is equivalent to that of the RSA algorithm.  Under a known
plaintext attack on the message, the security of the system rests
upon that of the one-way function.'

'..theyse public key cryptosystems hvae the potential of a fast
implementation.'


Has anyone looked into this paper?  Has anyone implemented the
cryptosystem explained in it?