Although there are many different aspects to consider when looking at
IT security, one of the most tried and trusted methods of ensuring the
safety of systems and data is to control people's access to them. In
this article the various complementary system-access control mechanism
s will be discussed. In addition, this article is aimed at demonstrati
ng that in order to tighten up control and security, it is important t
o think in terms of combining mechanisms by using various complementar
y technologies. This article, therefore, does not necessarily make a n
ew contribution to the domain of system-access control, but attempts r
ather to integrate and consolidate current approaches to improve it. E
mphasis is, therefore, placed on the inherent nature of the mechanisms
rather than on specific technologies such as biometrics. (C) 1997 Els
evier Science Ltd. All rights reserved.