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Add a Rust library and an example
More or less the first thing I did when I started this branch was researching the appropriate X25519 library to use. Now, almost 3 years later, I still find it rather hard to decide. My top picks were x25519_dalek, ed25519_compact and openssl bindings, in order of preference. But when I started with the Dalek crate, I encountered strange problems when using its getrandom feature, so I rewrote the thing for ed25519_compact. Quite a lot seems to have happened since then - I did not see any of the issues I had back then when I re-rewrote the thing just now.
This train of rewrites is the main motivation behind me implementing two versions of the API. I really wanted to have an interface that does not leak the underlying X25519 library - this is how we ended up with the untyped module. Happy to hear your thoughts, but I, for one, consider
fn tag(ours: &[u8; 32], theirs: &[u8; 32], ctr: u8, msg: &[u8]) -> [u8; 32]
... not as an improvement over C, so I wrote the typed module, too, which uses dalek types.
There is probably a third option, with an API that accepts traits and next to it a few impls for x25519 choices, but I don't think my Rust is up to that yet.
Looks interesting, but my Rust is at a hello world level, so probably can't do a good review here :)
This looks straightforward and simple now. Thank you! :D
I had one question on chat if you can now implement these traits from another crate. And two things I stumbled upon was the dalek import from lib and lib being no_std. But I'd be happy to merge this as-is. The PR is still technically in draft mode, though. (And I understand that there are the TODOs in the code, so maybe we still want to extend TagArgs a little bit before merging?
@nicmue could you please take a look at this PR, with particular attention to module structure, Rust best practices and the test implementation? I wonder if there's a better way to execute all test vectors for a given PublicKey/PrivateKey implementation.
@nicmue Thanks so much for the review, and sorry for taking some time to get back to it. This was really helpful, and now I know about clippy (and check, for that matter).
A follow-up to this PR should add these checks to CI.
@nicmue since you are now co-author here, do you want to sign Google's CLA? Alternatively, I can remove the Co-authored-by lines from the commits if you'd prefer.
@nicmue since you are now co-author here, do you want to sign Google's CLA? Alternatively, I can remove the
Co-authored-bylines from the commits if you'd prefer.
Sure why not. What do I need to do? :D
The CLA bot check failure has some info: https://github.com/google/glome/pull/175/checks?check_run_id=26263501184. tl;dr: sign in to https://cla.developers.google.com/clas and agree to the terms.
The CLA bot check failure has some info: https://github.com/google/glome/pull/175/checks?check_run_id=26263501184. tl;dr: sign in to https://cla.developers.google.com/clas and agree to the terms.
Done you can try to retrigger. :)