Re: Why only group1 diffie-hellman

[Aris Adamantiadis <aris@xxxxxxxxxxxx>]

Oops, I just see I misspelled your name. Apologies.

Aris

Le 8/07/11 16:39, Aris Adamantiadis a écrit :
> Hi Geraoid,
> 
> You are right that group14 only differ with the parameter. git master
> give the tools to fix it in the client in an hour or so (need to look at
> server support).
> Groupe-exchange is a little bit trickier, because client and server
> agree on a specific group (set of parameters) dynamically. I can see
> room for crypto mistakes in here.
> no pitfall forseen in group14.
> 
> Thanks for your help,
> 
> Aris
> 
> 
> 
> Le 8/07/11 16:34, Murphy, Gearoid P a écrit :
>> Aris + Andreas
>>
>> I would be interested in attempting this more as a technical exercise than anything else, if libssh can but the fruits of my labor to good use, then all the better. I would obviously defer to your collective expertise when it comes to the evaluation of the security of the submitted code.
>>
>> Unless I am gravely mistaken, the difference between group1 and group14 Diffie-Hellman kex is parametric only, there is no algorithmic change required, but the reply of Aris suggests that this is not the case, can anyone comment?
>>
>> Thanks
>>  - Gearoid
>> ________________________________________
>> From: Andreas Schneider [asn@xxxxxxxxxxxxxx]
>> Sent: 08 July 2011 14:55
>> To: libssh@xxxxxxxxxx
>> Subject: Re: Why only group1 diffie-hellman
>>
>> On Friday 08 July 2011 13:39:42 you wrote:
>>> Hi all
>>
>> Hi Gearoid,
>>
>>> Is there a particular design decision behind only only supporting  group1
>>> diffie-hellman key exchange?
>>
>> I don't think so, but we should support it.
>>
>>> I would be interested in attempting the implementation for group14
>>> diffie-hellman kex for integration into the libssh mainline
>>
>> RFC 4253 states that it MUST be supported. We would appreciate a patch for it.
>> Recently Aris added support for ecdh-sha2-nistp256 kex in master. It shouldn't
>> be to hard to add diffie-hellman-group14-sha1 now.
>>
>>
>>         -- andreas
>>
>> --
>> Andreas Schneider                   GPG-ID: F33E3FC6
>> www.cryptomilk.org                asn@xxxxxxxxxxxxxx
>>
>>
>>
>