Subject: RE: I-D ACTION:draft-deacon-xkms-aia-00.txt [SCVP-AIA]

From: Wen-Cheng Wang <[email-masked]>
Date: Sat, 6 Sep 2003 01:54:20 +0800 (CST)

Liaquat Khan wrote:
> Hi,
> Just on your last point...would the RP really trust the SCVP server
> blindly as you state??  
> I mean the RP would validate the signature on the SCVP response, would
> it not?  So it must have the SCVP self-signed certificate in its trust
> anchor list or be able to build a path from the SCVP certificate to a
> trusted certificate.  

Of course, the RP should validate the signature on the SCVP 
response. The question is how the RP can 'automatically' and
'safely' obtain the public-key of the SCVP server. I mean
the RP should be able to validate the signature without any
local configuration or installation in advance. If the RP
still needs to install the public-key of the SCVP server
into its PSE anyway, why not simply let the RP bind the URI
of the SCVP server with the public-key at the time of
installing the public-key? (I believe somebody already asked
similar question before.) IMO, if the SCVP server specified
in the certificate can not be 'automatically' trusted, then
add the URI of the SCVP server into the certificate does
not seem to be very useful. My last point is that if somebody
intend to invent a way to let the RP 'automatically' trust
some SCVP server, please be sure to also let it 'safely'
rather than 'blindly' trust the SCVP server.

BTW, I do not think the SCVP server certificate is a self-signed
certificate since I believe if the SCVP server have a certificate
it should be an EE certificate. The question is who should
be the issuer of the SCVP server certificate? It is very strange
that the current SCVP draft (draft-ietf-pkix-scvp-12) does not
mention anything about the format and the handling of the SCVP
server certificate. I believe that it is very tricky for the RP
to handling the SCVP server certificate included in the SCVP
reponse.

Instead of having a SCVP server certificate, another possibility
is to let the SCVP server distribute its public-key (maybe in the
raw format of the public-key rather than in the format of public-key
certificate) via a secure out-of-band channel. However, it seems
that the current SCVP draft rules out that kind of possibility
because it requires that the SCVP response MUST include the SCVP
server certificate.

Best regards,
Wen-Cheng Wang

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From: Stephen Kent <[email-masked]>
Date: Fri, 5 Sep 2003 14:46:11 -0400

Wen-Cheng Wang,

As I mentioned in one of my many messages today, there may be no need 
for an SCVP server to have a cert. If the server is used by only 
local clients, e.g., in an enterprise context, then the server's 
public key need not be signed by anyone. certainly, as your note, the 
server is an EE, not a CA, so the usual self-signed cert model may 
not apply.

Steve