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Re: [TLS] RI, TLS Extension tolerance and version tolerance in

"Yngve N. Pettersen (Developer Opera Software ASA)" <yngve@opera.com> Tue, 15 December 2009 11:31 UTC

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Date: Tue, 15 Dec 2009 12:30:33 +0100
To: David-Sarah Hopwood <david-sarah@jacaranda.org>, tls@ietf.org
From: "Yngve N. Pettersen (Developer Opera Software ASA)" <yngve@opera.com>
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Subject: Re: [TLS] RI, TLS Extension tolerance and version tolerance in
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On Tue, 15 Dec 2009 04:28:41 +0100, David-Sarah Hopwood  
<david-sarah@jacaranda.org> wrote:

> Yngve Nysaeter Pettersen wrote:
>> If the server does not support renegotiation then it might not support
>> the extension, but my proposal is that it MUST be TLS Extension
>> *tolerant*. I am however suggestion, optionally, that supporting the
>> extension should be a MUST in patched servers.
>
> It has to be a MUST. Otherwise,
>  - strict clients will unnecessarily abort the handshake when they
>    don't see the extension.
>  - lenient clients won't know to reconnect, so rollback attacks are
>    not necessarily prevented.
>

I am referring to supporting (recognizing) the RI extension in the Client  
Hello. Maybe that wasn't clear enough.

-- 
Sincerely,
Yngve N. Pettersen
 
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Opera Software ASA                   http://www.opera.com/
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