On 07/07/2023 21:28, Eric Rescorla wrote:
S 3.2.1
How much value are you getting from the CT logs? It seems like
additional complexity. I agree with your comment about having
this submitted to CCADB.
It seemed the fairest repeatable way to check whether a CA was
offering certificates to WebPKI clients without having to write a
lot of emails. I agree its not desirable to keep as a dependency
in the long run.
Can you elaborate on the concern here? I.e., is it that we will
overinclude or underinclude if we just use CCADB?
Sorry, this answer came out garbled. Using CT gives two things:
1) There are large extensions in end-entity certs which are specific to
the issuer and change little between certs. For example, the URLs for
OCSP, CRL and the practice statement are typically the same. Using CT
logs lets me pull out an example of each extension for that CA without
having to write a bunch of mails to ask them to produce them in the
right format.
2) I don't personally have concerns about the dictionary size and would
prefer to include every CA. However, if someone were to have strong
feelings about this then using CT to measure popularity is much fairer
than say scanning popular domains from the Tranco list or whatever.
In the long term, I hope this could just be removed and ideally the CA's
themselves provide a fixed size binary blob via CCADB that they'd like
compressed out of their certs.
Best,
Dennis
Thanks,
-Ekr
S 5.1.
ISTM that there are plenty of code points available.
Thanks!
Best,
Dennis
On Thu, Jul 6, 2023 at 3:18 PM Dennis Jackson
<ietf=40dennis-jackson...@dmarc.ietf.org> wrote:
Hi all,
I've submitted the draft below that describes a new TLS
certificate
compression scheme that I'm calling 'Abridged Certs' for now.
The aim is
to deliver excellent compression for existing classical
certificate
chains and smooth the transition to PQ certificate chains by
eliminating
the root and intermediate certificates from the bytes on the
wire. It
uses a shared dictionary constructed from the CA certificates
listed in
the CCADB [1] and the associated extensions used in end entity
certificates.
Abridged Certs compresses the median certificate chain from
~4000 to
~1000 bytes based on a sample from the Tranco Top 100k. This
beats
traditional TLS certificate compression which produces a
median of ~3200
bytes when used alone and ~1400 bytes when combined with the
outright
removal of CA certificates from the certificate chain. The draft
includes a more detailed evaluation.
There were a few other key considerations. This draft doesn't
impact
trust decisions, require trust in the certificates in the shared
dictionary or involve extra error handling. Nor does the
draft favor
popular CAs or websites due to the construction of the shared
dictionary. Finally, most browsers already ship with a
complete list of
trusted intermediate and root certificates that this draft
reuses to
reduce the client storage footprint to a few kilobytes.
I would love to get feedback from the working group on
whether the draft
is worth developing further.
For those interested, a few issues are tagged DISCUSS in the
body of the
draft, including arrangements for deploying new versions with
updated
dictionaries and the tradeoff between equitable CA treatment
and the
disk space required on servers (currently 3MB).
Best,
Dennis
[1] Mozilla operates the Common CA Database on behalf of Apple,
Microsoft, Google and other members.
On 06/07/2023 23:11, internet-dra...@ietf.org wrote:
> A new version of I-D, draft-jackson-tls-cert-abridge-00.txt
> has been successfully submitted by Dennis Jackson and
posted to the
> IETF repository.
>
> Name: draft-jackson-tls-cert-abridge
> Revision: 00
> Title: Abridged Compression for WebPKI
Certificates
> Document date: 2023-07-06
> Group: Individual Submission
> Pages: 19
> URL:
https://www.ietf.org/archive/id/draft-jackson-tls-cert-abridge-00.txt
> Status:
https://datatracker.ietf.org/doc/draft-jackson-tls-cert-abridge/
> Html:
https://www.ietf.org/archive/id/draft-jackson-tls-cert-abridge-00.html
> Htmlized:
https://datatracker.ietf.org/doc/html/draft-jackson-tls-cert-abridge
>
>
> Abstract:
> This draft defines a new TLS Certificate Compression
scheme which
> uses a shared dictionary of root and intermediate WebPKI
> certificates. The scheme smooths the transition to
post-quantum
> certificates by eliminating the root and intermediate
certificates
> from the TLS certificate chain without impacting trust
negotiation.
> It also delivers better compression than alternative
proposals whilst
> ensuring fair treatment for both CAs and website
operators. It may
> also be useful in other applications which store
certificate chains,
> e.g. Certificate Transparency logs.
>
>
>
>
> The IETF Secretariat
>
>
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