Explore Rustls and create an example

[bjoernQ]

Initially we can use RustCrypto to create a Rustls-Crypto-Provider (and later use HW-acceleration) to provide an alternative to mbedtls in cases where embedded-tls isn't enough (e.g. mutual authentication, server functionality etc.)

[bjoernQ]

Blocked by rustls/rustls#2068

[brody2consult]

I have been really busy working on rustls/rustls#2200 to enable building rustls for this kind of target. This is almost ready, with a few remaining XXX / TODO items that I would like to resolve soon. And I have a similar update for rustls-rustcrypto provider working here: brody2consult/rustls-rustcrypto#1

Bad news is that there may be some resistance due to the requirement for Rust nightly & issue with the built-in rustls providers: rustls/rustls#2068 (comment)

requires Rust nightly version

Perhaps this isn't a feature ready for mainline Rustls in this case?

One issue is that I had some trouble building the built-in aws-lc-rs & ring providers with the no atomic ptr targets.

I have similar feelings here. If this only works with rustls-rustcrypto, and not the two mainline crypto providers, is it ready to ship?

If they would reject my proposal or put it on hold, this would continue to block progress here.

I personally cannot see why they should reject a feature that could help some people in the embedded Rust community, even if the feature is clearly documented as an "unstable" feature that should only affect those who want to use the feature.

I would really appreciate it if anyone could help support my case to get my proposal accepted and included.

I would surely hate it if we could not use rustls without forking it.

[cpu]

Please note my questions shouldn't be read as intent to reject the proposal. I'm only one maintainer and don't set the project direction. I also haven't made a personal conclusion of whether it should/shouldn't be accepted, I'm only asking questions I think are relevant to evaluating the state of the work as part of a broader discussion.