The MAA explained below is based on "The message Authenticator Algorithm(MAA) and it's implementaion" by Davies and Clayden, published in 1988.[1]

Potential attack in the algorithm

In examining the algorithm a number of bodies tested its level of security.  One potential attack was found using a very large amount of chosen plain text in very long and artificial messages. To avoid this attack, the ISO standard 8731-2 has given a method on how to handle the problem when the message is very long. Simply saying, it has given the solution that messages longer than 1024 bytes shall be divided into segments of 1024 bytes and chained.

Implementation of the MAA:

Originally, the algorithm was designed to be implemented on a main frame computer. The implementation in high level languages is often proved slow in operation. For the highest speed the MAA needs to be written in assembly code.

A version of the MAA has been written by D W Davies in assembly code for the 6502. The coding in C has been done by D O Clayden. We compiled the C version of the code[2] and ran the program[3] for testing.