Pluggable Authentication Module

Pluggable Authentication Module (PAM) is a library for Linux which allow different session managers to authenticate users easily.

PAM provides an alternative to calling files like /etc/passwd by giving a high-level API that takes care of all the common functions required for a desktop.

It also takes care of managing keyrings or wallets.

The pam_unix module handles areas such as referring to /etc/passwd and /etc/shadow to verify credentials.