> On Feb 23, 2017, at 11:31 PM, Eric Mill <[email protected]> wrote:
> 
> On Thu, Feb 23, 2017 at 10:54 PM, Phillip Hallam-Baker via Public 
> <[email protected] <mailto:[email protected]>> wrote:
> 
> Things have to break before some people will act. Which is why I consider the 
> proposal to further reduce validity intervals to provide more procrastination 
> time positively harmful.
> 
> To restate this, you're saying that it's better to keep long-lived certs 
> around, so that the heightened damage their misissuance would do will 
> increase the motivation of CAs/browsers to deprecate weaker algorithms. 
> 
> I think that's a very difficult stance to defend. Holding one security 
> feature hostage to spur support for another doesn't seem likely to produce 
> security benefits, either in this case or the general case.

You are misrepresenting what I am saying. Do not put words in my mouth again. 
You do not speak for me. Only I speak for me.

Is that totally clear?


There is a WebPKI mechanism for dealing with certificates that were issued to 
people who should not have them. It is called revocation. It has been part of 
the PKIX specification from the very start. 

Revocation is required for much more than dealing with situations like 
DigiNotar. The vast majority of certificates that are revoked for cause were 
validly issued and then revoked because of actions by the subject like setting 
up a phishing site. 


If a browser provider decides not to support revocation as per the 
specification for the sake of shaving off a few milliseconds from their 
response, that is a choice they have made. They are the party that has decided 
to put their customers at risk. If they then go round pointing fingers at 
others for not mitigating the consequences of their decision, they are going to 
have the fingers pointed back to them.

In the PKIX architecture, the choice of certificate validity interval has no 
security consequences whatsoever. The only consequence of a longer or shorter 
validity interval is that the revocation infrastructure has to track 
certificate status for longer or shorter periods of time.

[This is not the case for self signed roots because they are not subject to 
revocation, however, they are not strictly speaking PKIX certificates either.]

If a party decides not to follow the PKIX architecture because they think they 
can provide the same security with a different technique, that is their 
prerogative. But they don’t then get to attack the rest of the industry and the 
millions of Web sites using certificates for not falling in line with their 
scheme.


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