Doug,
Thanks for the quick reply.
Douglas Stebila wrote:
On 2009-Jun-9, at 11:25 AM, Sean Turner wrote:
Other ECC documents in the IETF (TLS, SMIME, PKIX) indicate that
support for compressed keys are MAY while this draft says MUST NOT for
ECDSA and ECDH keys and MAY for ECMQV. What was the rationale for this?
Simplicity. In my opinion, compressed keys provide little benefit in
practice. Certainly for ECDH there's no reason to use them. I would be
willing to consider it as a MAY for ECDSA so that signing public keys
can be reused between standards.
I tend to agree. I think most people are just going to do uncompressed
and not bother with compressed. My concern is that somebody is going to
generate compressed keys use them for TLS sessions (because they are
allowed) and then not be able to use them for SSH. I'm not entirely
sure that people will reuse keys for TLS for SSH, but it might happen.
I guess I'm asking whether they should be MAY to match all the others
for interoperability sake?
Sec 3.1.2: In TLS/SMIME/PKIX, the signature value (r&s) are integers
but they are encoded together with the following syntax:
Ecdsa-Sig-Value ::= SEQUENCE {
r INTEGER,
s INTEGER
}
Any chance of reuse?
No. The signature above is encoded using DER encoding of an ASN.1
sequence. There is almost no use of ASN.1 in the secure shell
standards, so many SSH implementations may not have code to support DER
encoding and decoding. I prefer to stay with the basic syntax that the
secure shell standard provides. For those that do desire conversion
between the two, it is easy to implement given a DER library.
Fair enough I thought I'd give it a shot.
Does the Certicom IPR applies to this ID (it pretty much applies to
all the other ECC RFCs/IDs)?
According to
https://datatracker.ietf.org/ipr/1154/
draft-green-secsh-ecc is included in the list of documents to which the
IPR disclosure applies.
You are right it is listed there. I totally missed it.
spt
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