2026-09-29 07:01 UTC
Licensing question: I'm re-implementing an encoding scheme in Rust. I have a GPL-2 reference implementation in C that I check against.
The C source is 50-ish lines, the Rust reimplementation is 70-ish lines. Both are mainly a `switch`/`match` logic.
How free am I to choose another permissive license for the reimplementation?
As it's reimplementation of the algorithm, rather than copying the code, I don't think I'm bound by the GPL. I also haven't gone clean-room, as I was eyeballing the reference when writing the other, but I think that would only be relevant for patents.
Not looking for binding opinions, just discussion.
#freeSoftware #licensing
Replies (1)
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@simonzerafa@infosec.exchange 2026-09-29 08:55
@shtrom@piaille.fr Random comments from me would be If you take existing C code that is licensed under the GPL and rewrite or translate it into Rust, your Rust code is considered a derivative work under copyright law. The GPL would therefore seem to apply. If you go to the source algorithm and reimplemented it from scratch then you would probably need a clean room implementation. 🙂🖖