On Thu, Dec 01, 2016 at 04:36:17AM +0000, Peter Gutmann wrote: > Viktor Dukhovni <ietf-d...@dukhovni.org> writes: > > >So I'd like to see the text in the first paragraph changed to a SHOULD or > >worst-case a qualified "MUST whenever possible". > > Why is that whole thing even there in the first place? From the previous > discussions where this came up, the pretty much universal consensus was that > people were ignoring the requirement because it served no obvious purpose > but broke interoperability. Unless you're a server operator that chooses to > buy a whole bunch of $995 certs, one per algorithm, from a CA that allows > you to choose which algorithm gets used for signing, the whole thing is > completely inapplicable. You send whatever cert chain the CA gave you to > the client, and it's up to them to decide whether they want to accept or > reject. What would be lost by simply removing that entire block of text, > since it's being ignored by implementers anyway? The solution is to remove > it, not to fiddle with it until it becomes a no-op that matches what > everyone is doing anyway.
Using algorithms that are supported is kinda important for interop, since if you send a non-(super-)TA certificate using algorithm the client doesn't know, it is going to have trouble validating the chain. If you are referring to mixing RSA/ECDSA certs in one certificate chain, that already works fine in TLS-1.2-as-of-spec (unless client does something crazy[1]). TLS 1.3 removes the options for clients to be crazy here. [1] That's related to requirment of matching EE (not any CA) certificate type and ciphersuite, causing client to be able to trip all sorts of bugs and edge cases in ciphersuite selection. -Ilari _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
