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Re: [TLS] draft-rescorla-tls-renegotiate and MITM resistance

David-Sarah Hopwood <david-sarah@jacaranda.org> Tue, 10 November 2009 20:16 UTC

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Date: Tue, 10 Nov 2009 20:16:27 +0000
From: David-Sarah Hopwood <david-sarah@jacaranda.org>
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Subject: Re: [TLS] draft-rescorla-tls-renegotiate and MITM resistance
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Marsh Ray wrote:
> Is this allowed?
> 
>   |--- session A anon ---|
>   |--- session B anon ---||-- resumed A --|
> 
> I have heard that browsers may do this.

Ouch -- I thought that I understood the attack, and now you've just given
me another headache ;-)

Do servers support a renegotiation that resumes a different session?
That seems like a really bad idea.

Since a resumption may always be refused, clients can't be relying on
this behaviour. So we could compatibly specify that servers MUST NOT
accept such a resumption.

-- 
David-Sarah Hopwood  ⚥  http://davidsarah.livejournal.com

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