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Re: New confidentiality and integrity limits

Martin Thomson <mt@lowentropy.net> Thu, 25 June 2020 23:45 UTC

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Date: Fri, 26 Jun 2020 09:44:55 +1000
From: "Martin Thomson" <mt@lowentropy.net>
To: quic@ietf.org
Subject: Re: New confidentiality and integrity limits
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On Fri, Jun 26, 2020, at 04:29, Christopher Wood wrote:
> As Martin noted, for the integrity limit, the story is slightly 
> different. Key updates do not help there.

Or we don't know that they do...  There are still a lot of unanswered questions.  We do know that a forgery attempt against one key is likely still good for a different key on the same connection.  It might not be good for another connection (the inclusion of connection IDs might help us here, but that's another unknown - and unreliable - factor) but we can't really control for that.  So we chose something we believe to be both conservative and practical.

The forgery limits are still quite generous: if you have to drop a connection due to that many forgeries, then I'd suggest that something is seriously wrong.

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