[cabfpub] Updated Certificate Transparency + Extended Validation plan

Jeremy Rowley jeremy.rowley at digicert.com
Tue Feb 4 19:10:13 UTC 2014

I do not think this is correct.  The number of proofs actually increases as you decrease validity periods. A 2-year certificate only lets the customer skip a year in the renewal process.  A 2-year certificate will lower the number of certificates logged by one (since the customer would need to log two 1-year certificates instead of one 2-year certificate). The number of domains requiring a certificate identifies the quantity of proofs, not the number of certificates actually issued.


-----Original Message-----
From: agl at google.com [mailto:agl at google.com] On Behalf Of Adam Langley
Sent: Tuesday, February 04, 2014 12:05 PM
To: certificate-transparency
Cc: Jeremy Rowley; Ben Laurie; CABFPub; therightkey
Subject: Re: [cabfpub] Updated Certificate Transparency + Extended Validation plan

On Tue, Feb 4, 2014 at 1:58 PM, Doug Beattie <doug.beattie at globalsign.com> wrote:
> The number of proofs should be related to the reputation of the CA, 
> the number of years the CA has been in business

I think you're assuming that a larger number of proofs is designed to catch possible malpractice on the part of the CA, but that's not it at all.

The aim is to make sure that bad /logs/ can be distrusted. The major obstacle to killing logs is that certificates depend on the proofs and that, if we killed all the logs that a certificate was depending on, the site in question might go dark. In order to make sure that logs can be distrusted without blowback, the number of proofs increases as the duration of the certificate does. Thus, even if we kill one log every 12 months (which we certainly hope not to do!), longer lived certificates would still be functional towards the end of their lives.



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