3. Authentication

To tell legitimate users from hackers and other illegitimate users, network security uses an authentication process. Users are asked to identify themselves before they are given access to any network assets.

Username - Password

This is the commonest form of authentication. The person types in their username and password which is then checked against a database of legitimate users.

A straightforward username and password has some weaknesses however :-

• The person may not keep their login details confidential and so an unauthorised user gains access
• The password may be so weak that an unauthorised user guesses it or uses brute force software

Two factor authentication

This is becoming very popular for accessing secure sites and networks. The person enters an username-password then the service sends a text message containing a code to their mobile phone which they have to enter as well. Some banks provide their customers with a hardware device to create a one-time code which they have to enter.

Biometric authentication

This means some physical aspect of the person is used to confirm their identity. For example a fingerprint scanner or an eye scanner is used to authenticate.