[TLS] draft-shore-tks-dnssec-chains-extension

[Paul Wouters <[e-mail]>]

I do like the dnssec-chain-extension.

I think the server should stick to one chain, from the root to itself,
so it does not have to deal with variable chain blobs per client.
That will allow server code to stick to something like hourly
regenerating the blob for use with all clients.

I do strongly prefer the binary blob to be in raw dns format. That
will make parsing easier with existing code, and over time we will
not run into issues where dns libraries support newer algorithms
but this specific dnssec parsing code isn't updated.

The DNS answer packet format can contain many DNS records in the
Additional Section, without requiring any new DNS data format (and note
edns-query-chain also does not specify a new format). I would be fine
with stating the order of the additional records should be top down,
to make validation easier, although probably the TLSA record and RRSIG
itself should appear in the DNS Answer Section.

As for ekr's question on why not stuff this inside X.509, that would not
be compatible with tls raw pulic keys that only contain a SBKI, and drag
back into the protocol more ASN.1 parsing and containers.

Paul