[cabfpub] Draft Ballot 185 - Limiting the Lifetime of Certificates: User input

philliph at comodo.com philliph at comodo.com
Fri Feb 10 17:39:49 UTC 2017


I fail to see how this example shows a security improvement from reducing certificate validity.

In the case that CABForum declares that certs of a particular type are to be decorated with attribute X, there will naturally have to be a phase in period. The normal practice for such a phase in would be to grandfather all the existing CAs for the period of the phase in and require new entrants to start using the new decoration immediately. So the only practical impact of the phase in period is that clients would have to carry both sets of code for the duration of the phase in. If the period is three years instead of one, they have to carry the legacy grandfather code for 24 extra months.

That is an argument but it is not a security justification for the proposed change.


Note that CAs will probably have to support both OIDs until the relevant roots expire because many browsers are not updated.


> On Feb 10, 2017, at 12:04 PM, Ryan Sleevi <sleevi at google.com> wrote:
> 
> 
> 
> On Fri, Feb 10, 2017 at 8:58 AM, philliph--- via Public <public at cabforum.org <mailto:public at cabforum.org>> wrote:
> Which is the reason I think that making the change proposed for the reason proposed will actually make the WebPKI less secure, less robust.
> 
> s/reason proposed/reasons proposed/
> 
> Note the plural.
> 
> Absent this change, if Browsers were to require that all new certificates contain the id-kp-serverAuth EKU, from intermediates that contain the id-kp-serverAuth EKU, from roots that contain the id-kp-serverAuth EKU - as a very simple example - how long do you believe this migration would take?
> 
> Similarly, if Browsers were to require that all new EV certificates contain the CABForum EV OID, rather than the per-CA OID, how long do you believe this change should take?
> 
> Similarly, if Relying Parties want to be assured that all certificates they trust had their domain names validated via the methods in Ballot 169, rather than in the pre-169 or post-180 method, such as "The CA consulted a santeria to ensure that the domain was authorized" (under the basis of Any Other Method), when do you believe Relying Parties could have that confidence in the ecosystem?
> 
> Regrettably, I will find it necessary to highlight this every time it's advanced, because it's not the argument being presented, and needs to be corrected, lest this alternative fact be seen as correct through its continued repetition.

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