Talk:Authentication

It should be noted that the problem of authentication is not equivalent to the problem of authorisation. This article confuses the two!

The article needs to be split into two cross-referenced articles about these two closely related but different topics. The differences are subtle, and someone should write about them.

Strictly speaking, the types of authentication are:

• Something only the user is
• Something only the user has
• Something only the user knows

It is not really authentication (or at least, not good authentication) if the user is not the only one in possession of a particular credential.

There is also a fourth, seldom mentioned method of authentication that is often used but almost always in combination with at least one of the other forms:

• Some place the user is