Re: [TLS] Certificate compression draft

Ryan Sleevi <ryan-ietftls@sleevi.com> Tue, 07 March 2017 02:13 UTC

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From: Ryan Sleevi <ryan-ietftls@sleevi.com>
Date: Mon, 6 Mar 2017 21:13:46 -0500
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To: Vlad Krasnov <vlad@cloudflare.com>
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Subject: Re: [TLS] Certificate compression draft
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On Mon, Mar 6, 2017 at 5:37 PM, Vlad Krasnov <vlad@cloudflare.com> wrote:

> Don't know about neutral dictionary, but simply compressing Cloudflare
> cert using Google cert, gives an additional 6% using brotli -15.
>
> I would rather have a biased dictionary than none at all :)
>
> Cheers,
> Vlad


I can appreciate that sentiment, but you do realize the natural consequence
of that - it creates an incentive structure for the larger CAs to get
larger, by virtue of the compression benefits afforded to them by such a
dictionary making such certificates more desirable. That, in turn, results
in more instability and insecurity for the PKI ecosystem and penalizes
non-participants of the WebPKI within TLS.

While such a desire for improved compression is natural, the external costs
should not be underestimated or dismissed.

I would rather have no compression than a biased dictionary, given these
concerns.