Re: [DNSOP] DNSSEC as a Best Current Practice

[Masataka Ohta <[e-mail]>]

Bjorn Mork wrote:

> Sorry for being slow, but you'll have to explain a lot more than that if
> you want to convince me that DNS cookies and DNSSEC are equivalent
> alternatives.

In a sense, they are equivalent, because both plain DNS with
long enough message IDs and DNSSEC are subject to MitM attacks,
naturally with similar difficulties.

The point is that DNSSEC, or PKI in general, is not cryptographically
secure merely blindly trusting untrustworthy intermediate systems,
which means it is against the end to end principle, improperly
called TTPs (Trusted Third Parties).

In another sense, they are not equivalent because attack vectors
are different. MitM attacks can be on ISP chains, CA chains
or software distribution chains. The last example is applicable
to browser or DNSSEC resolver software containing some certificates
or public keys.

 > I was asking specifically for your alternative BCP. "Go figure it
 > out by yourself with DNS cookie or something like that" just doesn't
 > make it.

That's your problem not to able to understand that DNSSEC is *NOT*
cryptographically secure, which I have been pointing out for these
20 years, because it is subject to MitM attacks on CA chains, which
was demonstrated by diginotar about 10 years ago.

						Masataka Ohta