Re: [TLS] TLS 1.3 certificate delegation?

[Johannes Merkle <[e-mail]>]

> It is actually not a violation of PKIX.  However, behaviour is undefined.
> 
> PKIX (rfc5280) inherited this from X.509, and it has been spelled out
> in rfc5280-clarifications:
> 
>   http://tools.ietf.org/html/rfc6818#section-2
> 
>   2. Update to RFC 5280, Section 3.2: "Certification Paths and Trust"
> 
> 
>      Add the following paragraph to the end of RFC 5280, Section 3.2:
> 
>   | Consistent with Section 3.4.61 of X.509 (11/2008) [X.509], we note
>   | that use of self-issued certificates and self-signed certificates
>   | issued by entities other than CAs are outside the scope of this
>   | specification.  Thus, for example, a web server or client might
>   | generate a self-signed certificate to identify itself.  These
>   | certificates and how a relying party uses them to authenticate
>   | asserted identities are both outside the scope of RFC 5280.
> 

Interesting, this clarification in RFC 5280bis escaped my attention.

However, self-issued implies that both certificates share the same Common Name. So this paragraph only applies to the
scenario sketched by Andy when the server identity (sub domain) is encoded _only_ in SubjectAltName (dNSName). This is
recommended by RFC 2818 anyway.

-- 
Johannes