Owasp Testing Guide v4

Authentication Testing

Authentication (Greek: αυθεντικός = real or genuine, from 'authentes' = author ) is the act of establishing or confirming something (or someone) as authentic, that is, that claims made by or about the thing are true. Authenticating an object may mean confirming its provenance, whereas authenticating a person often consists of verifying her identity. Authentication depends upon one or more authentication factors.

In computer security, authentication is the process of attempting to verify the digital identity of the sender of a communication. A common example of such a process is the log on process. Testing the authentication schema means understanding how the authentication process works and using that information to circumvent the authentication mechanism.