Re: [TLS] Possible blocking of Encrypted SNI extension in China

Rob Sayre <sayrer@gmail.com> Tue, 11 August 2020 06:14 UTC

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From: Rob Sayre <sayrer@gmail.com>
Date: Mon, 10 Aug 2020 23:14:02 -0700
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To: Peter Gutmann <pgut001@cs.auckland.ac.nz>
Cc: Christian Huitema <huitema@huitema.net>, Christopher Wood <caw@heapingbits.net>, "TLS@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] Possible blocking of Encrypted SNI extension in China
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On Mon, Aug 10, 2020 at 10:58 PM Peter Gutmann <pgut001@cs.auckland.ac.nz>
wrote:

> Rob Sayre <sayrer@gmail.com> writes:
>
> >Do you think this fingerprinting will work with the newer ECH design, if
> the
> >client can add arbitrary content to the encrypted payload?
>
> ECH doesn't have any effect on web site fingerprinting so unless I've
> misunderstood your question the answer would be "N/A".
>

Assuming the definition here:
https://tools.ietf.org/html/draft-wood-pearg-website-fingerprinting-00

it does seem like ECH would make this more difficult, at least for pages in
a large anonymity set. (agree that it won't matter much for Twitter,
Google, et al)

thanks,
Rob