@alex, any chance you could take a look at this PR?

So, I'm not interested in including ossl params anywhere in the public API, I think they're a giant mistake and I hope OpenSSL gets rid of them.

I'd be ok:

• With a PR that just adds the -sys bindings
• Refactoring the private usage of OSSL_PARAMS to have a param builder or similar

But I'm not interested in any changes to the public APIs for this.

After working with params API to get things working in a non-deprecated way, I completely agree with you!

Regarding the comment about changes to the public APIs, there was a reason why I added the params mod as a non-public one, see: https://github.com/sfackler/rust-openssl/blob/5e26fd8465aa245c90cce7859d65817c34cc2ce4/openssl/src/lib.rs#L180-L181.
I left the visibility of everything else in that mod as pub because I was lazy. I can change it all to pub(crate) if you want?
Either way, I don't think I've changed the public API (and if I have, it was completely unintentional as I agree that the params stuff should be kept internal only).

@alex since #2451 went in (which implemented essentially the same functionality I had in this PR a month ago), please could I get some eyes on this?

(Merge conflict here, it's on my TODO to review Friday)

After rebasing my non-deprecated branch, I've realised I can drop the merge implementation (not to mention the lifetimes were completely borked too)!
No I can't, I still need it for upgrading DH Params -> Public -> Private!

@alex did you manage to get a chance to look at this one?

@alex did you get around to having some time to look at this one please?

@alex apologies for the delay, had some higher priority stuff to look at. Please could you cast your eyes over this one?
(See #2464 for how these changes fit in)