## Why Open Source?
All Public Lab work is **open source** unless clearly marked otherwise, including hardware and software. (Some prefer the term "free software" to "open source software"). This means that you're free to _use, modify, and redistribute_ it, as long as you open source your own contributions.
Why do we do things this way? By sharing our techniques and tools under open source licenses, we ensure that the **development process is open**, and that anyone can contribute. Open sourcing also ensures that nobody can take exclusive control of a project by using patents or copyrights to exclude others from using it.
### Sharing alike
For most of the projects at Public Lab, this also means that if you use these tools, **you are obliged to share any improvements or modifications you make under the same open source license**. Think of it as "giving something back" to everyone else who's helped to develop the technology.
## How to cite
A basic attribution line is as follows:
> [CC-BY-SA](https://creativecommons.org/licenses/by-sa/4.0/) 2017 Public Lab contributors
Even better is to cite specific contributors by their PublicLab.org username or their real name if they've shared that, for example:
> [CC-BY-SA](https://creativecommons.org/licenses/by-sa/4.0/) 2017 @shannon and other Public Lab contributors
Likewise, for the CERN OHL (for hardware):
> Released under the Open Hardware License, 2017 Public Lab contributors
## About the licenses
We use a number of licenses at Public Lab, depending on the project, the privacy a local partner needs, and whether we are licensing documentation, source code, hardware, map data, or something else.
**By publishing your work on this website, you agree to license your work under the CC-BY-SA, and CERN Open Hardware Licenses below.** Any work which you do not wish to license should be clearly marked as such.
## Public Domain
The legal concept of the Public Domain as related to copyright is primarily within the United States, where it refers to yielding or giving up all copyright, irrevocably. This means that **anyone** can reuse, republish, or adapt the content, _without asking permission or even attributing the authors_. Works produced by the federal government of the US are supposed to be automatically released into the Public Domain. For outside the US, the [Creative Commons Zero license](http://creativecommons.org/publicdomain/zero/1.0/), which attempts to be the equivalent of Public Domain, but internationally viable.
## Creative Commons: "CC"
These licenses, which can be read about at the [Creative Commons website](http://creativecommons.org), are easy-to read, thorough, and come in a few flavors, which can be mixed and matched. Much of our content is released under both **Attribution** and **Share-Alike** provisions, a combination typically referred to as "**CC-BY-SA**".
### Attribution: "BY"
One of the most basic licenses CC offers, this primarily requires that you attribute where you got the content, usually with a URL and credit line.
### Attribution-ShareAlike: "BY-SA"
The ShareAlike provision requires that derivative works be released under the same license. This tends to encourage users to "give back" -- sharing what they've done, re-contributing their improvements, additions, and changes back to the community. This means that any time you use, adapt, or republish content bearing this license, you must use the same license for your publication.
## CERN Open Hardware License 1.1
Public Lab hardware designs are released under the CERN Open Hardware License 1.1. You can read the license text here: http://publiclab.org/wiki/cern-ohl-11
### GNU General Public License v3
The PublicLab.org website (this one!) and most other Public Lab software is licensed under the GPLv3, although there are some exceptions which are under the GPLv2 or MIT license. Read more about [Public Lab software projects here](/wiki/software)...