An authentication system that uses something a user has in conjunction with something a user knows is called?

This method of authentication is known as two factor authentication. This means that there are two types of evidence required to prove your identity. This can be, like the question suggests, an identifying trait with regards the person - such as physical characteristics - and it is often a password in addition. Alternatively it can just be a set password and a randomizing entry code.

• What is an authentication system?

An authentication system is any system that operates to identify an individual, prove they are who they say they are and confirm if they are authorized to enter premises or access specific information. The most common form is a user-specific password, but passwords are easily stolen or lost, hence the rise in two factor authentication.

• What types of security are two factor?

All security can be two factor as long as there is an additional element aside a pass code. The most notable two factor authentication method is biometrics. This is the practice of scanning the retinas in the eyes, or scanning finger/hand prints to prove identity. Alternatives include voice recognition software and even simple technology such as a swipe card.

• Why use two factor authentication?

The idea behind such security is to lower the risk of an attack or a breach. By making the authentication require two types of proof, and often differing ones, it makes it harder for someone to infiltrate. These are known as attack vectors, and are classed as logical - a code - and physical - genetic identification.

Biometric identification is popular because of the fact that there is only one of you. Only your eyes and facial markings can be read. Fingerprints can be lifted and replicated, as we've seen in many films, but copying the other methods of identification are incredibly hard and are beyond almost all criminals.