Re: [Trans] Question about PRIVATE option (Ticket #1)

[Rick Andrews <[e-mail]>]

Rob,

What you're suggesting is that the add-pre-chain command can be used to log a cert that ultimately will not include the SCTs in the final cert? That seems like a path forward.

For the slight complication you describe, I suppose that needs to be added to the issue tracker.

-Rick

> -----Original Message-----
> From: Rob Stradling [mailto:[e-mail]]
> Sent: Tuesday, March 11, 2014 3:34 AM
> To: Rick Andrews; [e-mail]
> Subject: Re: [Trans] Question about PRIVATE option (Ticket #1)
> 
> Rick, thanks for raising this.  I agree that we need to make the
> PRIVATE
> option work in these scenarios.  As it happens, I mentioned this to Ben
> just before the trans meeting last week.
> 
> My suggestion is that we should permit both Certificate SCTs _and
> Precertificate SCTs_ to be delivered via OCSP Stapling and the TLS
> Extension.
> 
> There's no reason why a Precertificate couldn't be issued _after_ the
> corresponding Certificate has been issued!  :-)
> 
> Would this work for you?
> 
> 
> Slight complication...
> In the SCT v1 format, entry_type is "implicit from the context in which
> the SCT is presented."
> So, for the above idea to work, we would need to either:
>    i) Define SCT v2, in which entry_type is expressed explicitly.
>    or
>    ii) Define a CtExtensions extension to carry the entry_type
> explicitly in a v1 SCT.
>    or
>    iii) Expect TLS Clients to attempt to verify v1 SCTs sent via OCSP
> Stapling or the TLS Extension twice (first time, assume entry_type is
> "x509_entry"; if the SCT signature doesn't verify, try again, this time
> assuming entry_type is "precert_entry").
> 
> On 10/03/14 18:58, Rick Andrews wrote:
> > Regarding Issue #1: _http://tools.ietf.org/wg/trans/trac/ticket/1#_
> > "Need options for avoiding logging private subdomains", I think the
> > design is not yet complete.
> > I understand how this works when my customer has chosen the precert
> > delivery option (I mask the second level domain in the precert that I
> > send with the add-pre-chain command).
> > But if my customer has chosen to deliver SCTs via OCSP staple or TLS
> > extension, and they want to keep their subdomain private, what do I
> do?
> > I'm going to sign the cert without SCTs in it, but if I log it via an
> > add-chain command, the subdomains will be visible in the log.
> > -Rick
> 
> --
> Rob Stradling
> Senior Research & Development Scientist
> COMODO - Creating Trust Online