What Is an Open Source License?

What is an open source license?

What Is Open Source?

Open source refers to software whose source code, distributed through a licensing scheme, can be freely copied, modified, used, and redistributed. With open source, anyone can fix bugs or adapt the code to add features, and can participate in software development. In this way, open source provides developers with the right to distribute the program, the right to access the source code, and the right to modify the source code.

Open source is widely used because, when leveraged well, it can reduce development cost and time. However, quite a few users are not well aware of the legal responsibilities of open source and the risks that come with them.

  • Just like commercial software, to use open source you must comply with that open source’s license. If you violate it, your right to use it is revoked, and if you have turned it into a product, you cannot sell that product.
  • You may also face claims from the open source community, severely damaging your corporate image as a license-violating company.
  • In the worst case, you could become involved in legal litigation, so it is important to know about open source in advance and prepare accordingly. The legal responsibilities of open source differ depending on the type of open source license, so when using open source you must understand the legal responsibilities of each license.

Software Intellectual Property Rights

To understand the legal risks of open source, you need to understand the basic concepts of intellectual property rights in software and of licenses, because an open source license is a type of software license. The legal mechanisms that protect software — that is, the intellectual property rights related to software — include copyright, patent rights, trademark rights, and trade secrets.

Copyright is the right that a creator (author) acquires over their creation; it protects the result of the creation and arises at the same time as the creation. Therefore, when a programmer develops software, copyright arises automatically, and that right is granted to the programmer or the company they belong to. A copyrighted work may not be copied, distributed, or modified by anyone without the copyright holder’s permission.

Patent

A patent is an exclusive and exclusionary right that an inventor (patent holder) holds over an invention. Unlike copyright, a patent must be filed in a prescribed manner and only takes effect once it has passed examination and been registered. To use a patented technology, you must obtain the patent holder’s permission. Software that implements a patented method falls within the scope of the patent regardless of the programming language used.

CopyrightPatent
When the right arisesArises at the same time as creationPatent filing, examination, registration
Content of the rightMoral rights (right of publication, right of attribution, right to integrity)
Economic rights (reproduction, adaptation, distribution, transmission)
Exclusive and exclusionary right; right to work the invention
Scope of effectSubstantial similarity of expression (code)Identity of the idea (algorithm, function)

Software License

A rights holder who has an exclusive and exclusionary right over software may permit others to use or distribute that software. Simply put, a license is permission for others to use, copy, modify, distribute, and so on, one’s own work.

  • Typical commercial software requires a royalty in return.

Open Source License

Just like ordinary commercial software, open source also has intellectual property rights such as copyright. Therefore, if you use it carelessly without the rights holder’s permission, you may face litigation. However, open source rights holders grant broad licenses so that many people can use the software freely.

For example, they grant users not only the right to use the software but also to copy and distribute it freely, and even provide the source code so that it can be modified freely. For this, an open source license that explicitly expresses these rights is required. Therefore, software to which no open source license applies is not open source, and no one other than the copyright holder may use, copy, modify, or distribute that software.

Open source licenses do not require a royalty like commercial software does; instead, they require a few obligations to be observed, such as providing the source code.

Key Obligations

It is important to understand and comply with the obligations of open source. The general obligations of open source licenses are notice and source code disclosure.

Most open source licenses require that information about the developers or contributors and about copyright be displayed in or included with the product, and they require the distributor to attach a copy of the relevant license so that users can clearly understand their rights regarding the open source.

e.g.) Apache License 2.0
 
4. a. You must give any other recipients of the Work or Derivative Works a copy of
this License;
 
4. c. You must retain, in the Source form of any Derivative Works that You distribute,
all copyright, patent, trademark, and attribution notices from the Source form of the
Work, excluding those notices that do not pertain to any part of the Derivative Works;

Source Code Disclosure

Representatively, GPL-family licenses allow software to be distributed in binary form but require that the source code corresponding to the binary be disclosed together with it.

e.g.) GPL 2.0
 
3. You may copy and distribute the Program (or a work based on it, under Section 2) in
object code or executable form under the terms of Sections 1 and 2 above provided that
you also do one of the following:
 a) Accompany it with the complete corresponding machine-readable source code,

Applying the Same License Upon Redistribution

The part that differs greatly depending on the license concerns ‘Copyleft’. Copyleft licenses, represented by the GPL, require that when users modify software and wish to distribute it, the modified software also be distributed under the same license.

e.g.) GPL 2.0
 
2. You may modify your copy or copies of the Program or any portion of it, thus forming
a work based on the Program, and copy and distribute such modifications or work under
the terms of Section 1 above, provided that you also meet all of these conditions:
 b) You must cause any work that you distribute or publish, that in whole or in part
contains or is derived from the Program or any part thereof, to be licensed as a whole
at no charge to all third parties under the terms of this License.