OpenPAM is an implementation of PAM

Pluggable Authentication Modules

Pluggable authentication modules are a mechanism to integrate multiple low-level authentication schemes into a high-level application programming interface . It allows programs that rely on authentication to be written independent of the underlying authentication scheme...

 used by FreeBSD

FreeBSD

FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...

, NetBSD

NetBSD

NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...

, DragonFly BSD

DragonFly BSD

DragonFly BSD is a free Unix-like operating system created as a fork of FreeBSD 4.8. Matthew Dillon, an Amiga developer in the late 1980s and early 1990s and a FreeBSD developer between 1994 and 2003, began work on DragonFly BSD in June 2003 and announced it on the FreeBSD mailing lists on July...

 and Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

 (starting with Snow Leopard

Mac OS X v10.6

Mac OS X Snow Leopard is the seventh major release of Mac OS X, Apple's desktop and server operating system for Macintosh computers.Snow Leopard was publicly unveiled on June 8, 2009 at the Apple Worldwide Developers Conference...

),
and offered as an alternative to Linux PAM

Linux PAM

Linux Pluggable Authentication Modules provide dynamic authorization for applications and services in a Linux system. Linux PAM is evolved from the Unix Pluggable Authentication Modules architecture.There are four groups for independent management:...

 in certain Linux distributions.

OpenPAM was developed for the FreeBSD Project by Dag-Erling Smørgrav and NAI Labs, the Security Research Division of Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research program.

On 2008-01-08, OpenPAM was one of eleven projects selected by Coverity

Coverity

Coverity is a software vendor based in San Francisco. It was incorporated in November 2002. It develops static code analysis tools, for C, C++ and other programming languages, used to find defects and security vulnerabilities in source code...

 for promotion to Rung 2 of their DHS-funded Open Source Hardening Project, which tracks bugs found in open-source software

Open-source software

Open-source software is computer software that is available in source code form: the source code and certain other rights normally reserved for copyright holders are provided under a software license that permits users to study, change, improve and at times also to distribute the software.Open...

 by Coverity's Prevent static analysis

Static analysis

Static analysis, static projection, and static scoring are terms for simplified analysis wherein the effect of an immediate change to a system is calculated without respect to the longer term response of the system to that change...

 tool. On 2009-09-23, OpenPAM was promoted to Rung 3, along with Ruby

Ruby (programming language)

Ruby is a dynamic, reflective, general-purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. Ruby originated in Japan during the mid-1990s and was first developed and designed by Yukihiro "Matz" Matsumoto...

, Samba

Samba (software)

Samba is a free software re-implementation, originally developed by Andrew Tridgell, of the SMB/CIFS networking protocol. As of version 3, Samba provides file and print services for various Microsoft Windows clients and can integrate with a Windows Server domain, either as a Primary Domain...

 and Tor.