Cryptographic Keys

Another authentication method is the use of cryptographic keys and digital signatures to prove one’s identity. This can be an alternative to using passwords and
biometric systems or can be used in combination with these technologies.
A private key is a cryptographic key that should be available to only one person, and this is how it offers authentication purposes. It should be highly protected and not shared in any way. The private key can be used to create a digital
signature, which also provides authentication of a user. These items are covered
further in Chapter 6, but for now understand that they are mechanisms that can
be used for authentication purposes.