--On Wednesday, August 06, 2014 07:15 +0200 Patrik Fältström <paf@xxxxxxxxxx> wrote: > > On 6 aug 2014, at 04:26, Dave Crocker <dhc@xxxxxxxxxxxx> wrote: > >> Use DANE without DNSSec, and calling it opportunistic >> probably makes sense. Using it with DNSSec and it doesn't. > > The devil is in the details. I think we disagree on the > meaning of the word "opportunistic", and the evaluation of > whether you are lucky enough. > > Personally, I think that as fragile the current CA system is, > I think DANE without DNSSEC is more stable and better than the > current CA system. And better than self-signed-certs that one > "just accept" (which happens quite a lot). Conversely (and without agreeing or disagreeing with either of you), the discussion suggests noting, again, the very limited nature of what DNSSEC actually protects. It is ultimately an integrity test within the DNS hierarchy. If the resolver associated with the user's application is not DNSSEC-validating and within that user's trust boundary, then relying on DNSSEC for protection is only as good as the intermediate trust situation, e.g., whether the client user trusts the testing and validity assertions of her ISPs forwarding DNS system. There is reason to not do that. First, it may have changed but at least up to some years ago, those ISP "DNS servers" were much more often compromised than, e.g., authoritative servers for root or TLD domains. Second, some ISPs have discovered that that they have economic or political incentives to alter DNS queries or responses. Enough have done so under various circumstances to discourage uncritical trust. The other end is equally bad. DNSSEC protects the integrity of data already stored in the DNS. But, if the proverbial Bad Guy can compromise a domain name registrar and register a name that is misleading or otherwise problematic, certificates tied to that name may not be very useful, especially as assertions of good and upright behavior associated with, e.g., mail traffic. Whether DANE-type certificates that depend on DNSSEC and registrar integrity are more of less trustworthy than PKI-type certificates that depend on certificate chains, low-assertion-quality certificates, and CA integrity is an interesting question... but one that might easily be resolved by a race to the bottom. john