Re: [TLS] One approach to rollback protection

Nikos Mavrogiannopoulos <> Thu, 29 September 2011 06:35 UTC

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Date: Thu, 29 Sep 2011 08:38:11 +0200
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Subject: Re: [TLS] One approach to rollback protection
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On 09/29/2011 12:57 AM, Martin Rex wrote:

>> - Forward compatibility. How does a X-year old server that support TLS 1.2
>> understand that that new cipher suite code point is not some new cipher it
>> does not support, but an indication that the client support TLS 1.5? The
>> codepoints would have to not just be predictable, but the codepoints would
>> also have to work for TLS NG using protocol version 4.1. How far ahead do
>> we reserve codepoints, how much of the ciphersuite codepoint space will
>> this eat up? Or do we assume that any TLS 1.2+ server is version and
>> extension tolerant, so TLS 1.2 is the highest version we will ever need to
>> assign a code point for?

> I do _not_ want to retire the original TLS version negotiation,
> just like to see an alternative "hinting" being standardized to
> accomodate a ~10 year transition period to get over TLS version-related
> interop problems that exist in today's installed base.

For what reason? Since more and more people demand TLS 1.1 support more 
and more servers will make sure that they interoperate with it. Creating 
a new approach to negotiate versions might even create more 
interoperability problems. Why do you think implementers that got wrong 
the original simple negotiation will get right this one?