A passphrase is a longer version of which authentication factor?

A passphrase serves as an extended form of a password, often consisting of a sequence of words or a sentence that is longer and more complex. The main purpose of a passphrase is to enhance security by making it harder for unauthorized users to guess or crack, while still being easier for the user to remember compared to random strings of characters.

Using a passphrase takes advantage of the greater complexity and length than a traditional password, which typically consists of fewer characters and may be less secure. This is crucial in many authentication scenarios, especially where strong access controls are needed.

In contrast to other options, a username simply identifies the user and is usually not a secret; it does not function as an authentication factor itself. A token represents a physical device or generated code used in two-factor authentication, which is quite different from the concept of a passphrase. Similarly, a fingerprint is a biometric factor used in verification and is fundamentally distinct from what a passphrase represents in terms of security measures.