[DNSOP] Re: [art] Re: DNS-designated Public Key Author ities (DKA)

On Sun, Jun 21, 2026 at 7:09 PM S Kishore <[email protected]> wrote:
> Regarding the LLM: I did not know there was a policy saying that AI-assisted messages should say so.

To be clear, those recommendations are only my own, not the IETF's.

> Let's step back a bit and ask what a relying party needs from a key distribution framework. An RP needs two things: know where to find a key for an identifier, and what basis it has for trusting that key for a given use case?

I understand the idea of flexibility here, but I think it is unwise.
In the history of key distribution, I see a clear lesson that
simplicity is essential for security.  Pushing important decisions
about trust levels out to the relying parties does not work well in
practice.  A high, clear, uniform threshold should be our goal for
security.

In this specific case, relying on an insecurely resolved TXT record to
locate the DKA server permits trivial targeted attacks of a kind that
are well-known from the early WWW.  In my view, this weakness largely
invalidates the security value of the proposal.  Requiring DNSSEC
would resolve this, but it is far from universally deployed.
Additionally, clients often use DNS resolution APIs that do not
clearly indicate whether DNSSEC was used, and complex questions arise
when DNSSEC validation is performed externally by a recursive
resolver.

My preference would be to eliminate this TXT record from the design
entirely.  Instead, DKA discovery could proceed via HTTP .well-known
on the email domain, in-band via new SMTP commands (with TLS
authentication), or in many other ways that do not allow an attacker
to intercept and replace users' keys with their own.

--Ben

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