PAM provides Pluggable Authentication Modules.  It is a flexible,
dynamically configurable mechanism for authenticating users.

PAM provides a way to develop programs that are independent of
authentication scheme.  These programs need "authentication modules" to be
attached to them at run-time in order to work.  Which authentication module
is to be attached is dependent upon the local system setup and is at the
discretion of the local system administrator.

This package includes the dynamic and static libpam libraries,
developer files, and related programmer's man pages documenting
the functions.  Over 25 PAM modules are included. This is Linux-PAM;
it works with Solaris, NetBSD, AIX, and other operating systems.