Re: SSH in ECC Internet Draft

[nisse%lysator.liu.se@localhost (Niels Möller)]

Sam Hartman <hartmans-ietf%mit.edu@localhost> writes:

> I think you should look at how this will likely work in common
> implementations.  If your ECC library is likely to want to take ASN.1
> parameters as input, then that's probably how you want to transport
> them.

I don't buy that argument. By the same argument, the only reason not
to replace the "ssh-rsa" keys by the asn.1 based pkcs#x stuff formats
is backwards compatibility.

The way I see it, when you specify asn.1 as the wireformat for
anything, that forces every implementation (or the libraries it
depends upon) to take asn.1 to its core.

I see the ssh RSA and DSA key formats as a good example on how to do
things. It allows ssh implementatiions to use very simple and
minimalistic libraries. Whenever compatibility with other formats is
needed, that conversion can easily be done *off-line*, and without
automatically making bugs in the conversion code into remote root
exploits.

Converting between asn.1 formats and simpler native formats used for
the actual computation, is maybe no big deal in principle, but that's
no good reason to *force* that conversion code into each and every
implementation of the ssh protocol. You don't want code bloat in ssh
implementations.

Regards,
/Niels