What is open security?

David A. Wheeler

August 21, 2013

Institute for Defense Analyses

This document provides a definition of the term “open security,” along with some background, clarifications, and discussion.


Various government projects work to enable “open security” – but what does that term mean?  This article proposes an answer, along with background, clarifications, and discussion.

Proposed Definition

Open security is the application of open source software (OSS) approaches to help solve cyber security problems.  OSS approaches collaboratively develop and maintain intellectual works (including software and documentation) by enabling users to use them for any purpose, as well as study, create, change, and redistribute them (in whole or in part).  Cyber security problems are a lack of security (confidentiality, integrity, and/or availability), or potential lack of security (a vulnerability), in computer systems and/or the networks they are a part of.

In short, open security improves security through collaboration.


Modern society depends on computer systems for a myriad of functions, yet cyber security weaknesses enable attackers to subvert those computer systems.  Often attackers have the advantage— attackers can typically exploit systems by finding one or a few weaknesses, while defenders must eliminate or remediate a large number of potential vulnerabilities in large, complex systems.

In recent years OSS approaches have enabled widespread collaboration and produced high-quality, widely used products.  Widely used OSS programs include Linux (a key part of Android), the Apache web server, and the Firefox web browser.  OSS approaches have proven themselves in areas beyond software, e.g., Wikipedia uses OSS approaches to develop and maintain a remarkable encyclopedia.

Since OSS approaches have proven themselves useful in solving other problems, it seems reasonable to believe that OSS approaches could help solve some cyber security problems as well.

Defenders working together to eliminate and remediate vulnerabilities are likely to be far more effective than if they work in isolation.  For example, defenders as a group can be more innovative and more thorough, since with OSS approaches many different ideas can be quickly combined together.  OSS approaches are not free of cost, but since they often cost nothing to license and support can be competed, OSS solutions are often inexpensive and thus more likely to be used.

This is not to say that all solutions must necessarily be OSS, or that OSS approaches can solve all cyber security problems.  However, OSS approaches have much to offer in resolving current cyber security problems.


Open security is simply the application of OSS approaches to a particular type of problem, so it builds on existing OSS approaches.  People must be allowed to legally collaborate, so:

Intellectual works that have no copyright (e.g., a “work of the U.S. government” as defined in 17 USC 101) may provide these freedoms.  When they do, OSS approaches can also be applied to them.

Legally allowing collaboration is only the first step—the next is to actually collaborate.  There are many different ways to collaborate, and many tools that support it, but these can be varied depending on the needs of the collaborators.


The definition of open security could have been narrowed to apply only to software, or broadened to include work whose receivers have fewer rights.  These alternatives were rejected for the following reasons:

The open security definition is derived from the free software definition, because that definition is much shorter and simpler than the open source definition (the most likely alternative).  Formal U.S. Government definitions, such as the definition in the U.S. DoD 2009 policy [DoD2009], also use the free software definition as their starting point.

This definition of open security does not exclude “open hardware” per se, but the definition of the term “open hardware” is still in flux at the time of this writing.  Additionally, the current focus in the open security community is more on improving software and related documentation and less on hardware.  Thus, it seems appropriate to focus the definition and discussion on the better-understood areas, without excluding hardware in the future.


Simply defining the term “open security” does not solve cyber security problems.  However, a clear definition of “open security” makes it easy to determine whether an approach is, or is not, open security.

Since open security approaches have the potential to help solve serious problems, a clear definition will help people focus on determining where open security approaches can be best applied.


[Creative Commons] Creative Commons.  About The Licenseshttp://creativecommons.org/licenses/

[DoD2009] Department of Defense (DoD).  Clarifying Guidance Regarding Open Source Software (OSS). 2009-10-16. http://dodcio.defense.gov/Portals/0/Documents/FOSS/2009OSS.pdf

[FreedomDefined] Freedom Defined.  Definition of Free Cultural Workshttp://freedomdefined.org/Definition

[FSF] Free Software Foundation (FSF).  Free Software Definition.  2013-06-18.  http://www.gnu.org/philosophy/free-sw.html

[OSI] Open Source Initiative (OSI).  Open Source Definition (Annotated). Version 1.9. http://opensource.org/osd-annotated

[Wikimedia] Wikimedia Foundation.  Resolution: Licensing policy.  Passed 2007-03-23. http://wikimediafoundation.org/wiki/Resolution:Licensing_policy

This work was conducted under contract N66001-11-C-0001, subcontract D6374-S5, Task GT-5-3329 for the Georgia Tech Research Institute and Department of Homeland Security (DHS). The publication of this IDA memorandum does not indicate endorsement by the Department of Defense or Department of Homeland Security, nor should the contents be construed as reflecting the official position of those Agencies. The material may be reproduced by or for the U.S. Government pursuant to the copyright license under the clause at DFARS 252.227-7013 (NOV 95).