Re: SSH in ECC Internet Draft

[Joseph Galbraith <galb-list%vandyke.com@localhost>]

Bill Sommerfeld wrote:
> On Tue, 2006-10-10 at 11:17 -0500, Nicolas Williams wrote:
>> On Wed, Oct 11, 2006 at 01:52:24AM +1000, Damien Miller wrote:
>>> IMO that (some) ECC libraries happen to use ASN.1 is not a good reason
>>> to use it as protocol element.
>> The draft defines one ASN.1 type ('curves', a SEQUENCE of OIDs) where
>> existing SSHv2 constructs could be used instead.  The draft's other uses
>> of ASN.1/DER do not require an implementation of SSHv2 to implement
>> ASN.1/DER outside ECC libraries, but this one type does.
> 
> actually, it looks to me like there may be a deeper problem: the same
> "two level negotiation" issue which affected the gssapi key exchange.
> 
> I think you need to define a family of ssh key exchanges, one per
> defined "curve", so that two implementations which support
> noninteresecting sets of ECC curves but also support other KEX
> mechanisms can find other common mechanisms.

You could take the route that gssapi did and base64 encode
the curve oid and make it part of the name:

"ssh-ecc-<base64 encoded curve oid>,ssh-ecc-<a-different-oid>"

Thanks,

Joseph