signature::Signer support

[baloo]

Hi!

I was wondering if maybe you'd be open to have support for signature::Signer in the crate.
This would allow to separate the storage of a private key on a hardware token instead.

This is not a request for anyone to work on it, more a question to know whether such work could get merged eventually.

Thanks!

[dignifiedquire]

Generally I think it would be nice to support it, though I am curious how you see this working?

[baloo]

I'm not too sure yet. I wanted to ask before investing a significant amount of time in it.

I think moving a couple API towards generic (binding to the SecretKeyTrait) and creating an implementation of impl SecretKeyTrait for T where T: signature::Signer should do?
There might be more than that.

[dignifiedquire]

the issue is that a lot of the internals are enum bound, especially on the parsing side, so might run into issues there

[wiktor-k]

I think it's a great idea to keep in mind. I'm also interested in rpgp supporting various hardware tokens and utilizing common Rust traits would definitely make it easier. 👍

[baloo]

@wiktor-k nice to see you here too haha!

[wiktor-k]

@wiktor-k nice to see you here too haha!

Ha, yeah 👋 I remember you from the cryptoki repo which I also maintain... apparently we're interested in roughly the same stuff :)