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Re: [TLS] datacenter TLS decryption as a three-party protocol

Tony Arcieri <bascule@gmail.com> Wed, 19 July 2017 23:10 UTC

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From: Tony Arcieri <bascule@gmail.com>
Date: Wed, 19 Jul 2017 16:09:40 -0700
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To: Benjamin Kaduk <bkaduk@akamai.com>
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Subject: Re: [TLS] datacenter TLS decryption as a three-party protocol
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On Wed, Jul 19, 2017 at 6:09 AM, Benjamin Kaduk <bkaduk@akamai.com> wrote:

> As Stephen noted in his presentation, a lot of the proposals for passive
> decryption can be seen as trying to turn TLS from a two-party protocol into
> a three-party protocol.  Which is probably the right way to think about it,
> even when all (three) parties are within the same administrative domain.
>
> Stephen also said something about it being hard to shoehorn a three-party
> protocol into the API for a two party protocol.
>

Trying to turn a two-party protocol into a three party protocol is a
classical source of confused deputy vulnerabilities:

http://www.hpl.hp.com/techreports/2009/HPL-2009-20.pdf

This is why I have been such a strong proponent of using something like a
TLS extension for this sort of thing if it is to happen. At least that way
we get mutual client and server consent.

-- 
Tony Arcieri

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