Open Source Licenses

Open source licenses grant permission for anybody to use, modify, and share licensed software for any purpose, subject to conditions preserving the provenance and openness of the software.

Types

Copyleft

Weak and strong copyleft (as opposed to copyright) licenses attempt to make all software based on any open source components also have similar FOSS licensing on any derivative work. In other words, if you make something from a copyleft licensed project, you must use the same license. Examples:

GNU General Public License version 2.0 and 3.0 (GPL-2.0/GPL-3.0)

Permissive

These licenses impose minimal restrictions (if any) on how any subsequent users can implement, modify, or extend the software for open source or proprietary purposes. Examples include the MIT License

MIT license (MIT)
Apache License 2.0 (Apache-2.0)
BSD 2-Clause License (BSD-2-Clause) [also called “Simplified BSD” or “FreeBSD”] BSD 3-Clause “New” or “Revised” license
GNU Library or “Lesser” General Public License (LGPL)
Mozilla Public License 2.0
Common Development and Distribution License
Eclipse Public License version 2.0

MIT License

Permissive Type

Origin

A joint project in 1983 between IBM, MIT, and Digital Equipment Corporation (DEC) seems to be the origin of the MIT license and it is one of the most commonly used licenses.

Terms

The primary terms and conditions of the MIT license are to grant permissions and indemnify developers for future use. Specifically, it grants any person who obtains a copy of the software and associated files the right to use, copy, modify, merge, distribute, publish, sublicense, and sell copies of the software.

The only condition required to use the software is to include the same copyright notice in all copies or any substantial portions of the software. The final portion of the text provides for limitations and revokes any warranty implied by sharing the code. It allows any user to do anything with the code, granted they provide attribution and do not claim any liability in the future.

How to Use

To use the MIT license, developers need to copy the text as provided and include in source files as applicable. If using any other MIT licensed software in the project, retain the original license information at the top of the file, while keeping the copyright statements (if unchanged).

Commercial Use MIT licenses allow commercial use. Users do not have to provide any other source code when releasing new software. Including the attributions and original MIT license in the reused code will suffice.

Apache 2.0

Permissive

Origin

In 2000, the Apache Group (later the Apache Software Foundation) created the Apache License 1.1, in which derived products are no longer required to include attribution in their advertising materials, only in their documentation. In January 2004, ASF decided to depart from the BSD model and produced the Apache License 2.0. The stated goals of the license included making it easier for non-ASF projects to use, improving compatibility with GPL-based software, allowing the license to be included by reference instead of listed in every file, clarifying the license on contributions, and requiring a patent license on contributions that necessarily infringe a contributor’s own patents.

Terms

The Apache License does not require a derivative work of the software, or modifications to the original, to be distributed using the same license but it still requires application of the same license to all unmodified parts.

If a NOTICE text file is included as part of the distribution of the original work, then derivative works must include a readable copy of these notices within a NOTICE text file distributed as part of the derivative works, within the source form or documentation, or within a display generated by the derivative works (wherever such third-party notices normally appear)

The Apache License includes:

Grant of Copyright License – Grants a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare Derivative Works of, publicly display, publicly perform, sublicense, and distribute the Work and such Derivative Works in Source or Object form.
Grant of Patent License – Grants a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work to which such Contribution(s) was submitted. If You institute patent litigation against any entity (including a cross-claim or counterclaim in a lawsuit) alleging that the Work or a Contribution incorporated within the Work constitutes direct or contributory patent infringement, then any patent licenses granted to You under this License for that Work shall terminate as of the date such litigation is filed. Redistribution. You may reproduce and distribute copies of the Work or Derivative Works thereof in any medium, with or without modifications, and in Source or Object form, provided that You meet the following conditions:

You must give any other recipients of the Work or Derivative Works a copy of this License; and
You must cause any modified files to carry prominent notices stating that You changed the files; and
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; and
If the Work includes a “NOTICE” text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License.
You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License.

Submission of Contributions – Unless You explicitly state otherwise, any Contribution intentionally submitted for inclusion in the Work by You to the Licensor shall be under the terms and conditions of this License, without any additional terms or conditions. Notwithstanding the above, nothing herein shall supersede or modify the terms of any separate license agreement you may have executed with Licensor regarding such Contributions.
Trademarks – This License does not grant permission to use the trade names, trademarks, service marks, or product names of the Licensor, except as required for reasonable and customary use in describing the origin of the Work and reproducing the content of the NOTICE file.
Disclaimer of Warranty – Unless required by applicable law or agreed to in writing, Licensor provides the Work (and each Contributor provides its Contributions) on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are solely responsible for determining the appropriateness of using or redistributing the Work and assume any risks associated with Your exercise of permissions under this License.
Limitation of Liability – n no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall any Contributor be liable to You for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising as a result of this License or out of the use or inability to use the Work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if such Contributor has been advised of the possibility of such damages.
Accepting Warranty or Additional Liability – While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability

To use the Apache 2.0 license, the user need to copy the text as provided. In every licensed file, original copyright, patent, trademark, and attribution notices must be preserved (excluding notices that do not pertain to any part of the derivative works). In every licensed file changed, a notification must be added stating that changes have been made to that file.

Commercial Use

This licenses allow commercial use. Users do not have to provide any other source code when releasing new software. Including the attributions and original license in the reused code will suffice.

GNU GENERAL PUBLIC LICENSE Version 2&3 (GPL-2.0/GPL-3.0)

Copyleft

Origin

The development of GNU, a Unix-like operating system, started in January 1984, is known as the GNU Project. Many of the programs in GNU are released under the auspices of the GNU Project. The name “GNU” is a recursive acronym for “GNU’s Not Unix.” GNU is typically used with a kernel called Linux but itself is NOT Linux. GNU/Linux is used by millions, though many call it “Linux” by mistake.

The GPL was written by Richard Stallman in 1989, for use with programs released as part of the GNU project. The original GPL was based on a unification of similar licenses used for early versions of GNU Emacs (1985), the GNU Debugger, and the GNU C Compiler. These licenses contained similar provisions to the modern GPL, but were specific to each program, rendering them incompatible, despite being the same license. Stallman’s goal was to produce one license that could be used for any project, thus making it possible for many projects to share code.

The second version of the license, version 2, was released in 1991. Over the following 15 years, members of the free software community became concerned over problems in the GPLv2 license that could let someone exploit GPL-licensed software in ways contrary to the license’s intent. These problems included tivoization (the inclusion of GPL-licensed software in hardware that refuses to run modified versions of its software), compatibility issues similar to those of the Affero General Public License, and patent deals between Microsoft and distributors of free and open-source software, which some viewed as an attempt to use patents as a weapon against the free software community.

Version 3 was developed to attempt to address these concerns and was officially released on 29 June 2007.

Terms

Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

The GPLV2 was the former licenses released in 1991 while the most recent, the GPLV3, was released in 2007.
GPLV3 is longer compared to the GPLV2 since it almost tried to cover the same issues with the former license.
GPLV3 has more clarity on patent licenses, mostly on the wording of the license as it cannot be interpreted as “too broad.” It also applies to the protection of the patents unlike the GPLV2.
The GPLV2 has loopholes that the GPLV3 is trying to fix. The loophole has acquired the term Tivoization which is derived from a digital video recorder which captures television programming and saves the data into an internal hard drive storage for future viewing.
GPLV2 has a new section that has been added to the license called Protecting Users’ Legal Rights from Anti-Circumvention Law. The section’s intention is to prevent the GPVL3 from being included in technology or products that would be used to enforce the Digital Millennium Copyright Act (DCMA).
GPLV3 code is more compatible with more licenses compared to the former license.

How to Use

Here’s a brief summary of what you need to do to release a program under one of our licenses:

Get a copyright disclaimer from your employer or school.
Give each file the proper copyright notices. Make sure to clearly identify which versions of the license users can use.
Add a COPYING file with a copy of the GNU GPL or GNU AGPL.
Also add a COPYING.LESSER file with a copy of the GNU LGPL, if you use that.
Put a license notice in each file.

Commercial Use

This license does not allow commercialization, if someone creates derivative work it is required to have the GPL license as well and is provided for free

BSD licenses

Permissive

Origin

The original BSD Unix license was first written in 1969 and was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.

BSD is both a license and a class of license (generally referred to as BSD-like). The modified BSD license (in wide use today) is very similar to the license originally used for the BSD version of Unix. The BSD license is a simple license that merely requires that all code retain the BSD license notice if redistributed in source code format, or reproduce the notice if redistributed in binary format. The BSD license (unlike some other licenses e.g. GPL) does not require that source code be distributed at all..

Prior to 1999, the BSD License contained the following provision:

All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the University of California, Lawrence Berkeley Laboratory.

This provision seems relatively innocuous. It seems both reasonable and natural that the creator, having surrendered the exclusive right to commercially exploit a work, should receive credit not only in the acknowledgment of rights but in the advertising as well. It does not challenge the essential premises of open source, as it does not limit the scope of the use of the software in any direct way. Nonetheless, the pre-1999 BSD License sometimes causes problems because of this clause. The principles of open source endorse the commercial exploitation of software, including the sale of software, manuals, and support for profit. Such commercial exploitation very well may include advertising and when an open source project draws from a number of predecessors, the requirement of including such references can become a real burden. The BSD License, however, was amended in 1999 and this clause was removed.

Terms

The BSD UNIX license states one may copy, modify and redistribute the code so long as one retains a copy of the original copyright statement.

The copyright statements must include a clear statement of restrictions for use of the distributed software.

A disclaimer for limitations of liability that include not claiming authorship of the code where the code was not written by the user and not suing the author of the program for unexpected or undesirable functionality.

The stipulation that one doesn’t use the name of the software or its authors to advertise or promote work derived from modification of the distributed code without prior written consent.

Similarly, other BSD licenses can have these clauses but may not include them all. As a base, the first two clauses are a part of any BSD license. There are two, three and four clause BSD licenses.

The only substantial difference between this license and the MIT License is the non-attribution provision in the last clause. This provision requires prior permission for use of the name of the creator, and it protects the reputation of the creator from being explicitly associated with derivative versions of the program. Such restrictions permit creators to protect themselves from the injury to their reputations that can result from association with a defective or poorly written program, while still allowing others to use or modify a work.

How to Use

To use the BSD license, developers need to copy the text as provided and include in source files as applicable.

Commercial Use

This licenses allow commercial use. Users do not have to provide any other source code when releasing new software.

Links

https://www.synopsys.com/blogs/software-security/top-open-source-licenses/ https://choosealicense.com/licenses/ https://opensource.org/licenses-draft MIT License