For clarity, I think we need to discuss all the knobs along with proposed 
effective dates and usage periods so we get the whole picture.  The max 
validity period of the certificate has been the one receiving the most 
discussion recently, yet that’s missing from your counter proposal.  Don’t you 
view that as a critical data item to put on the table, even if less important 
(in your opinion) than domain validation re-use?.  

 

Did you add Public key as a new knob, meaning that Applicants must change their 
public key according to some rule?

 

 

From: Ryan Sleevi <r...@sleevi.com> 
Sent: Monday, March 16, 2020 10:27 AM
To: Doug Beattie <doug.beat...@globalsign.com>
Cc: r...@sleevi.com; Kathleen Wilson <kwil...@mozilla.com>; 
mozilla-dev-security-pol...@lists.mozilla.org
Subject: Re: About upcoming limits on trusted certificates

 

No, I don't think we should assume anything, since it doesn't say anything 
about lifetime :)

 

The value of reduced certificate lifetimes is only fully realized with a 
corresponding reduction in data reuse.

 

If you think about a certificate, there are three main pieces of information 
that come from a subscriber:

- The public key

- The domain name

- (Optionally) The organization information

 

In addition, there are rules about how a CA validates this information (e.g. 
the BR validation requirements)

This information is then collected, into a certificate, using a certificate 
profile (e.g. what the BRs capture in Section 7).

 

Reducing the lifetime of certificates, in isolation, helps with the agility of 
the public key and the agility of the profile, but does not necessarily help 
with the agility of the validation requirements nor the accuracy of the domain 
name or organization information. BygoneSSL is an example of the former being 
an issue, while issuing certificates for organizations that no longer exist/are 
legally recognized is an example of the latter being an issue.

 

These knobs - lifetime, domain validation, org validation - can be tweaked 
independently, but tweaking one without the others limits the value. For 
example, reducing domain validation reuse, without reducing lifetime, still 
allows for long-lived certs to be issued for otherwise-invalid domain names, 
which means you're not getting the security benefits of the validation reuse 
reduction. Introducing improved domain validation methods, for example, isn't 
helped by reducing lifetime or organization data reuse, because you can still 
reuse the 'old' validations using the less secure means. So all three are 
linked, even if all three can be independently adjusted.

 

I outlined a timetable on how to reduce the latter two (domain and organization 
validation). Reducing the latter two helps meaningfully reduce lifetimes, to 
take advantage of those reductions, but that can be independently adjusted. In 
particular, reducing lifetimes makes the most sense when folks are accustomed 
to regular validations, which is why it's important to reduce domain validation 
frequency. That effort complements reductions in lifetimes, and helps remove 
the concerns being raised.

 

On Mon, Mar 16, 2020 at 10:04 AM Doug Beattie <doug.beat...@globalsign.com 
<mailto:doug.beat...@globalsign.com> > wrote:

Are we to assume that the maximum certificate validity remains at 398 days?

 

From: Ryan Sleevi <r...@sleevi.com <mailto:r...@sleevi.com> > 
Sent: Monday, March 16, 2020 10:02 AM
To: Doug Beattie <doug.beat...@globalsign.com>
Cc: r...@sleevi.com <mailto:r...@sleevi.com> ; Kathleen Wilson 
<kwil...@mozilla.com <mailto:kwil...@mozilla.com> >; 
mozilla-dev-security-pol...@lists.mozilla.org 
<mailto:mozilla-dev-security-pol...@lists.mozilla.org> 
Subject: Re: About upcoming limits on trusted certificates

 

Hi Doug,

 

Perhaps it got mangled by your mail client, but I think I had that covered?

 

I've pasted it again, below.

 

Counter proposal:

April 2021: 395 day domain validation max

April 2021: 366 day organization validation max 

April 2022: 92 day domain validation max

September 2022: 31 day domain validation max

April 2023: 3 day domain validation max

April 2023: 31 day organization validation max

September 2023: 6 hour domain validation max

 

As mentioned in the prior mail (and again, perhaps it was eaten by a grueful 
mail-client)

This sets an entirely timeline that encourages automation of domain validation, 
reduces the risk of stale organization data (which many jurisdictions require 
annual review), and eventually moves to a system where request-based 
authentication is the norm, and automated systems for organization data is 
used. If there are jurisdictions that don't provide their data in a machine 
readable format, yes, they're precluded. If there are organizations that don't 
freshly authenticate their domains, yes, they're precluded.
Now, it's always possible to consider shifting from an account-authenticated 
model to a key-authenticated-model (i.e. has this key been used with this 
domain), since that's a core objective of domain revalidation, but I can't see 
wanting to get to an end state where that duration is greater than 30 days, at 
most, of reuse, because of the practical risks and realities of key 
compromises. Indeed, if you look at the IETF efforts, such as Delegated 
Credentials or STAR, the industry evaluation of risk suggests 7 days is likely 
a more realistic upper bound for authorization of binding a key to a domain 
before requiring a fresh challenge.

 

Hopefully that helps!

 

On Mon, Mar 16, 2020 at 9:53 AM Doug Beattie <doug.beat...@globalsign.com 
<mailto:doug.beat...@globalsign.com> > wrote:

Ryan,

 

In your counter proposal, could you list your proposed  milestone dates and 
then for each one specify the max validity period, domain re-use period and Org 
validation associated with those dates?    As it stands, Org validation 
requires CA to verify that address is the Applicant’s address and that 
typically involves a direct exchange with a person at the organization via a 
Reliable Method of Communication.  It’s not clear how we address that if we 
move to anything below a year.

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