Authen::passphrase is the base class for a system of objects that encapsulate passphrases. an object of this type is a passphrase recogniser: its job is to recognise whether an offered passphrase is the right one. for security, such passphrase recognisers usually do not themselves know the passphrase they are looking for; they can merely recognise it when they see it. there are many schemes in use to achieve this effect, and the intent of this class is to provide a consistent interface to them all, hiding the details.

this package contains implementations of several specific passphrase schemes in addition to the base class.