Comment by chrisballinger

I've been pretty quiet about this, but over the last couple of months I have been trying to negotiate with Moxie a way to distribute the GPL licensed AxolotlKit on the iOS App Store in ChatSecure (which is open source). After being denied a license, I was told by Moxie that I would be unable to write a non-GPL AxolotlV3 implementation because there is not publicly available documentation, and that any re-implementation will necessarily be a derivative work because the source code must be consulted. You may notice the AxolotlV2 documentation has been removed... and there was never documentation for AxolotlV3. The only public spec is the original double ratchet, and a few blog posts, which don't include things like signed prekeys and 4-way DH.