Preparing Rustls for Wider Adoption

It took me a minute to work out who &#x27;a better internet&#x27; aka ISRG are. It&#x27;s the folk behind Let&#x27;s Encrypt. That&#x27;s cool.<p>Anyway, this sounds great to me. I&#x27;m not a huge fan of memory unsafe languages, especially for critical code.

How does this compare to the verified TLS implementation from Project Everest?<p><a href="https:&#x2F;&#x2F;project-everest.github.io&#x2F;" rel="nofollow">https:&#x2F;&#x2F;project-everest.github.io&#x2F;</a><p><a href="https:&#x2F;&#x2F;mitls.org&#x2F;" rel="nofollow">https:&#x2F;&#x2F;mitls.org&#x2F;</a>

Happy to answer any questions that come up!

Rustls is really cool. I came to it because one of my projects used a library that in turn (by default) used OpenSSL. After much tinkering and not getting OpenSSL play well on that particular system I switched to Rustls and it worked out of the box and like a charm.<p>That being said and from what I understand Rustls is not a drop in replacement and it is not that easy for all Rust libraries which use TLS.<p>Which brings me to the point that I think a big leap forward for wider Rustls adoption in the Rust world itself would be to make it easily usable with all popular and widely used Rust libraries that depend on a TLS implementation.<p>What I would like to see is sort of a global (not per dependency)<p><pre><code> features = [&quot;rustls-tls&quot;] </code></pre> so that all libraries and their dependencies use Rustls automatically and OpenSSL is completely out of the picture. I know that this is not on Rustls alone but on the library writers too, but still it would be really cool to switch the TLS implementation like that.<p>Then we could even dream to make Rustls the default and use OpenSSL (or one of its relatives) only if need be.

Back when rustls was initially announced, people criticized how few ciphersuites it supported, like only TLS1.3 and parts of TLS 1.2. Not sure, I might have been among them. And it still doesn&#x27;t support TLS 1.1 or TLS 1.0. But since then, browsers have dropped support for many of those ciphersuites, so it&#x27;s far less interesting to implement support for them at this point.

Rustls is still not formally verified. It may not have memory errors, but there are a lot of other security errors besides just that (and there may be more of them since it hasn&#x27;t been used as much as open|boringssl has been used). It&#x27;s a slight improvement at best.<p>Ideally you want a formally verified SPARK or CompCert C implementation of TLS, but those are not open sores compilers so they won&#x27;t fly.

Does it allow building as a completely shared library? If not, everything using it will have to be rebuilt from scratch on each update, which is highly annoying and a security issue on its own IMO. Apparently it has a Rust API, so it&#x27;s probably unlikely.