As required by our threat model (among other reasons), the software developed to support the anonymous communication network we call I2P must be freely available, open source, and user modifiable. To meet these criteria, we make use of a variety of legal and software engineering techniques so as to remove as many barriers to entry for those considering making use of or contributing to the I2P effort.
While the information below may be more confusing than just simply stating “I2P is BSD”, “I2P is GPL”, or “I2P is public domain”, the short answer to the question “How is I2P licensed?” is this:
All software bundled in the I2P distributions will allow:
- use without fee
- use with no restrictions on how, when, where, why, or by whom is running it
- access to the source code without fee
- modifications to the source
Most of the software guarantees much more - the ability of anyone to distribute the modified source however they choose. However, not all of the software bundled provides this freedom - the GPL restricts the ability of developers who wish to integrate I2P with their own applications that are not themselves open source applications. While we applaud the noble goals of increasing the resources in the commons, I2P is best served by removing any barriers that stand in the way of its adoption - if a developer considering whether they can integrate I2P with their application has to stop and check with their lawyer, or conduct a code audit to make sure their own source can be released as GPL-compatible, we lose out.
Component licenses
The I2P distribution contains several resources, reflecting the partitioning of the source code into components. Each component has its own license, which all developers who contribute to it agree to - either by explicitly declaring the release of code committed under a license compatible with that component, or by implicitly releasing the code committed under the component’s primary license. Each of these components has a lead developer who has the final say as to what license is compatible with the component’s primary license, and the I2P project manager has the final say as to what licenses meet the above four guarantees for inclusion in the I2P distribution.
| Component | Source path | Resource | Primary license | Alternate licenses | Lead developer |
|---|---|---|---|---|---|
| I2P SDK | core | i2p.jar | Public domain | BSD, Cryptix, MIT | zzz |
| I2P Router | router | router.jar | Public domain | BSD, Cryptix, MIT | zzz |
| Ministreaming | apps/ministreaming | mstreaming.jar | BSD | Public domain, Cryptix, MIT | zzz |
| Streaming | apps/streaming | streaming.jar | Public domain | BSD, Cryptix, MIT | zzz |
| I2PTunnel | apps/i2ptunnel | i2ptunnel.jar | GPL + exception | Public domain, BSD, Cryptix, MIT | zzz |
| Routerconsole | apps/routerconsole | routerconsole.war | Public domain | — | zzz |
| Address Book | apps/addressbook | addressbook.war | MIT | Public domain, Cryptix, BSD | — |
| Susidns | apps/susidns | susidns.war | GPL + exception | — | — |
| Susimail | apps/susimail | susimail.war | GPL + exception | — | — |
| I2PSnark | apps/i2psnark | i2psnark.jar | GPL + exception | — | zzz |
| [BOB](/docs/legacy/bob/) Bridge | apps/BOB | BOB.jar | WTFPL | — | sponge |
| [SAM](/docs/api/samv3/) Bridge | apps/sam | sam.jar | Public domain | Cryptix, BSD, MIT | zzz |
| [SAM v1](/docs/legacy/sam/) Perl library | apps/sam/perl | SAM.pm | GPL | Public domain, Cryptix, BSD, MIT | BrianR |
| [SAM v1](/docs/legacy/sam/) C library | apps/sam/c | libSAM | BSD | Public domain, Cryptix, MIT | Nightblade |
| [SAM v1](/docs/legacy/sam/) Python library | apps/sam/python | i2p.py | Public domain | BSD, Cryptix, MIT | Connelly |
| [SAM v1](/docs/legacy/sam/) C# library | apps/sam/csharp/ | n/a | Public domain | BSD, Cryptix, MIT | smeghead |
| Other apps not mentioned | apps/ | ... | Probably Public domain but check the source | — | — |
| Installer | installer | install.jar, guiinstall.jar | Public domain | GPL + exception, BSD, Cryptix, MIT | — |
GPL Exception
While it may be redundant, just for clarity the GPL’ed code included within I2PTunnel and other apps must be released under the GPL with an additional “exception” explicitly authorizing the use of Java’s standard libraries:
In addition, as a special exception, XXXX gives permission to link the
code of this program with the proprietary Java implementation provided by Sun
(or other vendors as well), and distribute linked combinations including the
two. You must obey the GNU General Public License in all respects for all of the
code used other than the proprietary Java implementation. If you modify this
file, you may extend this exception to your version of the file, but you are not
obligated to do so. If you do not wish to do so, delete this exception statement
from your version.
All source code under each component will by default be licensed under the primary license, unless marked otherwise in the code. All of the above is summary of the license terms - please see the specific license for the component or source code in question for authoritative terms. Component source locations and resource packaging may be changed if the repository is reorganized.
Website License
Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License .
Commit Access
Developers may push changes to a distributed git repository if you receive permission from the person running that repository. See the New Developer Guide for details.
However, to have changes included in a release, developers must be trusted by the release manager (currently zzz). In addition, they must explicitly agree with the above terms to be trusted. That means that they must send one of the release managers a signed message affirming that:
- Unless marked otherwise, all code I commit is implicitly licensed under the component’s primary license
- If specified in the source, the code may be explicitly licensed under one of the component’s alternate licenses
- I have the right to release the code I commit under the terms I am committing it
If anyone is aware of any instances where the above conditions are not met, please contact the component lead and/or an I2P release manager with further information.