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Verifying based on DNS records is only a baseline. CAs can and do require more. If you want higher security for your domain, you can: 1. Make business arrang

by agwa 10y ago

Verifying based on DNS records is only a baseline. CAs can and do require more. If you want higher security for your domain, you can: 1. Make business arrangements with a handful of CAs to require additional verification when issuing certificates for your domain. 2. Use public key pinning to restrict your domain to those CAs. 3. Monitor certificate transparency logs to ensure that your chosen CAs are only issuing authorized certificates, and that other CAs are not issuing certificates for your domain. (CT does not have full coverage yet, but it has already done more to improve PKI security than DNSSEC has.) If one of your chosen CAs violates your trust, you drop them like a hot potato. DNSSEC removes this agility, leaving you at the mercy of your registrar and every zone operator higher than you in the hierarchy.

Kadin 10y ago
You're already at the mercy of every CA whose certificates are trusted by default by browsers. You can request additional verification, but that's not going to stop someone from turning the screws on a CA on the other side of the planet, whose certificates are nonetheless accepted-by-default by users' systems, and as long as they're not totally foolish in deploying that cert (i.e. it's used in targeted attacks only), you'd never see it via certificate transparency. (And yes, for the record, HPKP blunts the compromised-CA weapon somewhat, but adoption has been pretty crummy. IIRC the latest iOS Safari and IE don't support it at all.)
- tptacek 10y ago
  HPKP works no matter how many people adopt it. The most important sites on the Internet are all generally pinned (very few of them are DNSSEC-signed). Moreover, the surveillance aspect of HPKP doesn't require IE and Safari adoption. Chrome and Firefox are way more than substantial enough to make the risk of detection not worth the reward of trying to deploy a forged certificate. Note how many times in the past few years Google has slapped down CAs for "accidentally" issuing Google certificates.
- agwa 10y ago
  The end game for certificate transparency is that browsers will reject a certificate unless the server can prove that it has been submitted to at least two logs. In fact, as of the next version of Chrome, this will be required of all Symantec certificates due to their past misdeeds. The fact that HPKP and CT have not been fully adopted yet is not a good argument against them when the alternative under discussion is DNSSEC+DANE, which has seen even less adoption and doesn't even solve the problem.

by agwa 10y ago

Kadin 10y ago

You're already at the mercy of every CA whose certificates are trusted by default by browsers. You can request additional verification, but that's not going to stop someone from turning the screws on a CA on the other side of the planet, whose certificates are nonetheless accepted-by-default by users' systems, and as long as they're not totally foolish in deploying that cert (i.e. it's used in targeted attacks only), you'd never see it via certificate transparency. (And yes, for the record, HPKP blunts the compromised-CA weapon somewhat, but adoption has been pretty crummy. IIRC the latest iOS Safari and IE don't support it at all.)

tptacek 10y ago
HPKP works no matter how many people adopt it. The most important sites on the Internet are all generally pinned (very few of them are DNSSEC-signed). Moreover, the surveillance aspect of HPKP doesn't require IE and Safari adoption. Chrome and Firefox are way more than substantial enough to make the risk of detection not worth the reward of trying to deploy a forged certificate. Note how many times in the past few years Google has slapped down CAs for "accidentally" issuing Google certificates.
agwa 10y ago
The end game for certificate transparency is that browsers will reject a certificate unless the server can prove that it has been submitted to at least two logs. In fact, as of the next version of Chrome, this will be required of all Symantec certificates due to their past misdeeds. The fact that HPKP and CT have not been fully adopted yet is not a good argument against them when the alternative under discussion is DNSSEC+DANE, which has seen even less adoption and doesn't even solve the problem.