Add sop frontend

[link2xt]

There is a standard CLI interface: https://datatracker.ietf.org/doc/html/draft-dkg-openpgp-stateless-cli-08
Latest version of the draft is at https://dkg.gitlab.io/openpgp-stateless-cli/

Implementing it will allow to run OpenPGP interoperability test suite

[teythoon]

Implementing the Rust SOP interface (https://docs.rs/sop) now gives you the CLI frontend for free.

[dkg]

Implementing the Rust SOP interface would be a great way to confirm interoperability with the rest of the ecosystem!

[dignifiedquire]

@dkg yes, it is on my todo list, but unfortunately so are many other things 😭

[dkg]

i know the feeling, @dignifiedquire -- you have my sympathies. Have things shifted around any that you might be able to take a crack at it? #125 points to some stumbling blocks that @teythoon ran into when trying to write a sop-rs backend. And even a partial implementation is a useful starting point.

Or, maybe some other rpgp dev might be interested in working on creating this mapping? Maybe it'd be a job for someone coming up to speed on the project?

[hko-s]

I've spent a bit of time with https://crates.io/crates/sop, and the "OpenPGP interoperability test suite", both of which are excellent!

The result of my hacking so far is the experimental and still somewhat incomplete https://crates.io/crates/rsop

[hpk42]

No need to keep this issue open anymore, phew! thanks a lot @hko-s @dignifiedquire and @link2xt for pushing through all the issues/PRs in the last weeks! 🥳
And to @teythoon for the base work and the integration into https://tests.sequoia-pgp.org/ 💜
and of course to @dkg for persevering and long-running background work!