Re: [TLS] draft-sheffer-tls-bcp: DH recommendations

james hughes <hughejp@mac.com> Wed, 18 September 2013 16:46 UTC

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From: james hughes <hughejp@mac.com>
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Date: Wed, 18 Sep 2013 09:45:51 -0700
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To: "Blumenthal, Uri - 0558 - MITLL" <uri@ll.mit.edu>
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Subject: Re: [TLS] draft-sheffer-tls-bcp: DH recommendations
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On Sep 18, 2013, at 9:13 AM, "Blumenthal, Uri - 0558 - MITLL" <uri@ll.mit.edu>; wrote:

> I believe that for ephemeral DH 2048 bits is a huge overkill. In fact, 1536 is likely to be an overkill as well. I think 1280 bits would be sufficient for the next few years, and perhaps ECC patents will expire by then? In any case, I'd vote against anything (ephemeral DH-related :) larger than 1536 bits.
> 
> TNX!
> 
> P.S. It should be obvious that PFS is *far* more important than protecting one session key.

Please read my posting of 9/10. 2048 is required now. In this case it seems that the French government is providing sound advice. 

On Sep 10, 2013, at 9:00 AM, james hughes <hughejp@me.com>; wrote:

> Lastly, going a partial step seems strange also. Why do we what to put ourselves through this again so soon? The French government suggests 2048 now (for both RSA and DHE), and will only last 6 years. From 
> 	http://www.ssi.gouv.fr/IMG/pdf/RGS_B_1.pdf
> 
>> La taille minimale du module est de 2048 bits, pour une utilisation ne devant pas depasser lannee 2020.
> The minimum size of the modulus is 2048 bits for use not to exceed 2020.
> 
>> Pour une utilisation au-dela de 2020, la taille minimale du module est de 4096 bits
> For use beyond a 2020, the minimum module size is 4096 bits
> 
> 
> Pardon the bad cut/paste and google translate, but I believe you get the point.