Re: [TLS] DSA should die

mrex@sap.com (Martin Rex) Thu, 02 April 2015 02:17 UTC

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To: Dave Garrett <davemgarrett@gmail.com>
Date: Thu, 2 Apr 2015 04:17:23 +0200 (CEST)
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From: mrex@sap.com (Martin Rex)
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Subject: Re: [TLS] DSA should die
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Dave Garrett wrote:
> On Wednesday, April 01, 2015 08:40:40 pm Stephen Farrell wrote:
>> <no-hats-except-the-330+-ciphersuites-is-crap-hat>
>> 
>> Here's a suggestion: why pick 'em off one by one? How about
>> creating a new registry that only includes stuff we think is
>> really good for TLS1.3?
> 
> I don't think a whole new registry is a good idea. The ClientHello
> has to stay the same for backwards compatibility, and cipher suites
> will need to be listed for TLS 1.2 compatibility at least.
> Creating a whole new system is only good if you can completely
> ignore the old one.
> 
> There's plenty of space in the current registry if you want to
> start over. Just say 0xD000 and up is for TLS2 suites, and all
> below are TLS1. (at this point it's definitely time for 2.0)
> Define TLS2 codepoints for valid combinations for TLS2 and the TLS1
> would be invalid to negotiate for TLS2 but in there for TLS1.

I agree that ClientHello needs to remain backwards-compatible.

But how about using the Cipher Suites registry in a more creative fashion.

For TLSv1.3, we could do the negotiation through he cipher suites list
more like this:

   0x10,0xXX    specifies a key exchange algorithm (XX) 256 codepoints
   0x12,0xYY    specifies an authentication algorithm (YY) 256 codepoints
   0x14,0xZZ    specifies a symmetric encryption scheme (ZZ) 256 codepoints
   0x16,0xQQ    specifies a mac algorithm (QQ) 256 codepoints
   0x18,0xPP    specifies a PRF algorithm (PP) 256 codepoints

(with a little room in between if we ever exceed the 256 codepoints)


-Martin