Linux Pluggable Authentication Modules (PAM) is a suite of libraries that allow a Linux system administrator to configure methods to authenticate users.
It provides a flexible and centralized way to switch authentication methods for secured applications by using configuration files instead of changing application code.
[1] There are Linux PAM libraries allowing authentication using methods such as local passwords, LDAP, or fingerprint readers.
[2] Linux PAM is evolved from the Unix Pluggable Authentication Modules architecture.
[3] Linux-PAM separates the tasks of authentication into four independent management groups:[4]