authentication service An authentication service is a structured network service that determines that the digital ID being presented to a network service is being used by the real-world individual who has the rights to use it. This is often achieved through the use of a username/password combination or a digital certificate, depending on the degree of assurance required. (Excerpt from JISC Information Environment Glossary) 7 7 0.4 http://www.ariadne.ac.uk/sites/all/datacharts/hc/1793-chart-wp.html