[stir] Questions on the draft-ietf-stir-passport-04 integrity mechanism

[Ben Campbell <[e-mail]>]

Hi,

I have a couple of high level questions about the new integrity mechanism in draft-ietf-stir-passport-04. Apologies if these have already been discussed.

1) Do I understand correctly that the certificate used to sign a PASSporT with an rcdi claim MUST include a constraint for the _value_ of the digest? That is, if someone makes any change to any of the information they would normally include in an rcd claim, the signing party must get a new cert?

My concern is that, for good or bad, commercial callers really like to control the customer experience. Many like to change things up all the time. I can imagine things like special date-specific logos (e.g. Google doodles), “sale” badges on logos, distinctive branding for different “campaigns”, etc.  I realize things like ACME make the process of getting a new cert lighter weight than it used to be, but is it reasonable to require a new cert for any change?

This might be worse for third-party signers who may sign on behalf of many callers, each of which keeps changing things.

2) If I understand correctly, if anything in the rcd claim includes a URL, the rcdi claim incorporates the associated content. What about URLs?  For example, lets say a jcl key links to a jCard, and that jCard has a LOGO element with a URI? Is the alleged logo content at that URI protected?

I assume the answer is that the answer is no; otherwise it could be URLs all the way down and we have to stop somewhere. This is probably a matter of signer or issuer) policy. If so, it might be worth having some operational guidance that they need to think about such things.