The Message Authenticator Algorithm (MAA) was one of the first cryptographic functions for computing a Message Authentication Code. It was designed in 1983 by Donald Davies and David Clayden at the National Physical Laboratory (United Kingdom) in response to a request of the UK Bankers Automated Clearing Services.
The MAA was adopted, between 1987 and 2001, in international standards ISO 8730 and ISO 8731-2 to ensure the authenticity and integrity of banking transactions.
Later, cryptanalysis of MAA revealed various weaknesses, including feasible brute-force attacks, existence of collision clusters, and key-recovery techniques. For this reason, MAA was withdrawn from ISO standards in 2002.