The Data Security group understood the cryptosystems of that time, and started to build their own computer security techniques. Group members published various materials on data security. They studied methods of managing keys; identified particular keys which should be avoided with DES because they gave less security than normal and also they studied network protocols with security built in. They held a well-attended course on security in data communication at NPL in May 1981. They developed Message Authenticator Algorithm (MAA), based on the digital signature principle. As a result of these activities and involvement in commercial lecturing and publishing, notably a book by Davies and Price, "Security for computer network", they succeeded in attracting considerable consultancy business. His team was consulted by many organizations including UK banks and government agencies.
One of the major contributions of the group, especially D W Davies and D O Clayden was the development of Message Authenticator Algorithm which is explained below in detail.
Message Authenticator Algorithm (MAA):
Message Authenticator Algorithm (MAA) was initially published in 1983 and was developed based on the digital signature principle. The designers were D W Davies and D O Clayden. It has become a part of ISO standard 8731-2: Approved Algorithms for Message Authentication. The algorithm attracted the attention of the Committee of the London Clearing Banks and then Technical Committee 68 (Banking) of the International Standards Organization, which adopted it as one of the approved algorithms for message authentication.
