While the absolute strictest approach on GitHub is to reserve all rights (i.e., not apply any public license, defaulting to full copyright), the most restrictive publicly available license frequently encountered for non-software content is the Creative Commons Attribution-NonCommercial-NoDerivs (CC-BY-NC-ND) license. This license allows for extremely limited use of the work.
Understanding Strictness on GitHub
The term "strictest GitHub license" can refer to different levels of restriction depending on the type of content (software code vs. other content like documentation, art, or datasets) and whether the license is public or completely proprietary.
Creative Commons Attribution-NonCommercial-NoDerivs (CC-BY-NC-ND)
For non-software projects, especially creative works or documentation, the Creative Commons Attribution-NonCommercial-NoDerivs (CC-BY-NC-ND) stands out as the most restrictive among the widely recognized Creative Commons licenses.
- Attribution (BY): Users must give appropriate credit, provide a link to the license, and indicate if changes were made.
- NonCommercial (NC): Users cannot use the material for commercial purposes. This means no revenue generation, no advertising, and no commercial gain.
- NoDerivatives (ND): Users are not allowed to distribute modified versions of the work. If they remix, transform, or build upon the material, they may not distribute the modified material.
This combination ensures that while others can download and share the work, they cannot profit from it or change it in any way for redistribution. It's a popular choice for authors and artists who want to share their work publicly but maintain strong control over its usage and integrity.
Proprietary Licenses and "All Rights Reserved" for Software
For software projects, the strictest "license" is often the absence of an open-source license, which defaults to "All Rights Reserved" under standard copyright law. This means that, by default, no one can legally reproduce, distribute, or create derivative works from your code without explicit permission.
Developers can also create custom proprietary licenses that grant very limited, specific rights (e.g., internal use only, no distribution, no modification). These are typically the strictest forms of intellectual property control for software hosted on GitHub, as they actively prevent the freedoms commonly associated with open-source software.
Types of License Restrictions
To better understand what "strictest" means in different contexts, consider the permissions typically granted or denied by licenses:
| Permission Type | "All Rights Reserved" (No Public License) | CC-BY-NC-ND (Non-Software) | Permissive Open-Source (e.g., MIT) | Copyleft Open-Source (e.g., GPL) |
|---|---|---|---|---|
| Commercial Use | Generally Prohibited | Prohibited | Permitted | Permitted |
| Modification | Prohibited | Prohibited (for redistribution) | Permitted | Permitted |
| Distribution | Prohibited | Permitted (original only, non-commercial) | Permitted | Permitted |
| Sublicensing | Prohibited | N/A | Permitted | Permitted |
| Liability | N/A (Full Copyright) | Limited (often includes disclaimers) | Disclaimed | Disclaimed |
| Attribution Req. | Not Applicable | Required | Required | Required |
Note: For "All Rights Reserved," all actions are prohibited unless specific permission is granted by the copyright holder.
Practical Insights and Use Cases
- When to use CC-BY-NC-ND:
- Creative Works: Artists, photographers, or writers sharing portfolios or digital art.
- Educational Materials: Educators publishing lecture notes or course content they want to prevent commercialization of.
- Documentation: Project documentation where the author wants to prevent others from selling modified versions.
- When to use "All Rights Reserved" or a Proprietary License:
- Commercial Software: Companies developing closed-source applications they intend to sell licenses for.
- Internal Tools: Software developed for internal company use that should not be shared or modified by external parties.
- Early-Stage Projects: Projects where the owner is not yet ready to commit to an open-source model but wants to maintain full control.
Choosing the "strictest" license depends entirely on the project owner's goals regarding control, distribution, modification, and commercial use. For those who want to publish content on GitHub but retain maximum control over its commercial exploitation and derivative works, the CC-BY-NC-ND for non-software and a proprietary approach (or no public license) for software are the most restrictive options.
