I'm in favor of keeping redaction in, even with the added complexity.
Considering the number of enterprises that currently use domain names as a
directory, I think redaction is the difference between wide spread adoption
v. a single implementation for EV certificates. Since the intended
beneficiaries of CT are primarily the website owners, giving them insight on
certs issued to domains, it's up to the domain owner to have a policy for or
against redaction of their domain names.   

-----Original Message-----
From: Trans [mailto:[email protected]] On Behalf Of Andrew Ayer
Sent: Wednesday, June 15, 2016 11:57 AM
To: Trans <[email protected]>
Subject: Re: [Trans] Name redacted pre-cert can correspond to multiple certs

On Wed, 15 Jun 2016 10:00:27 +0100
Ben Laurie <[email protected]> wrote:

> On 10 June 2016 at 15:16, Rob Stradling <[email protected]>
> wrote:
> > I think it's fair enough to say that if you withhold information 
> > from CT, CT won't help you as much as it otherwise would have done.
> >
> > I see the attraction of replacing "redacted labels not with '?' but 
> > with a salted cryptographic hash of the label, with the salt 
> > specified in the Redacted Labels Certificate Extension", but I'd 
> > prefer to avoid increasing complexity.
> 
> I also like this suggestion. It does have the obvious downside that 
> dictionary attacks work, though they can be made expensive.

A sufficiently-long random salt makes dictionary attacks infeasible.
Since the salt is only specified in the certificate, anyone who knows the
salt knows the unredacted labels already.

Regards,
Andrew

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