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Re: [TLS] ECHO padding review and some open issues

Rob Sayre <sayrer@gmail.com> Fri, 24 April 2020 18:32 UTC

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From: Rob Sayre <sayrer@gmail.com>
Date: Fri, 24 Apr 2020 11:31:47 -0700
Message-ID: <CAChr6SwODhAugAKLxQyrbFjCqSd0SJgs9Q--Ypcs1H0bD9t8Xw@mail.gmail.com>
To: Christopher Wood <caw@heapingbits.net>
Cc: "TLS@ietf.org" <TLS@ietf.org>
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Subject: Re: [TLS] ECHO padding review and some open issues
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On Thu, Apr 23, 2020 at 4:31 PM Christopher Wood <caw@heapingbits.net>
wrote:

>
> Is this PR ready to go? If not, why not? What would you change, and why?
> (Concrete suggestions are highly encouraged!) Note also that this is
> currently only a recommended padding algorithm. Implementations are
> therefore free to do what they wish. Is this acceptable? Do we need to be
> more prescriptive? Food for thought!
>

It took me a while to notice that many of the padding debates aren't so
important if ECHO allows arbitrary structs/extensions in the encrypted
ClientHello. The recommendation is fine as a minimum, as long as servers
are tolerant of unknown extensions in the ciphertext.

thanks,
Rob

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