Certificate Management Service for the Session Initiation Protocol (SIP)
draft-ietf-sip-certs-15

This part was a DISCUSS:

In Section 7.5:

   The NOTIFY MUST contain a multipart/mixed (see [RFC2046]) body that
   contains both an application/pkix-cert body with the certificate and
   an application/pkcs8 body that has the associated private key
   information for the certificate.  The Content-Disposition MUST be set
   to "signal" as defined in [RFC3204].

   A future extension MAY define other NOTIFY bodies.  If no "Accept"
   header field is present in the SUBSCRIBE, the body type defined in
   this document MUST be assumed.

Question: does the Accept header field body contains "multipart/mixed"
or "application/pkcs8"? How would this work for future extensions if
there is a need to return other media types inside a top level "multipart/mixed"?

---------------------------------------

4.  UA Behavior with Certificates

   The Subscriber needs to decide how long it is willing to trust that
   the certificate it receives is still valid.  If the certificate is
   revoked before it expires, the Notifier will send a notification with
   an empty body to indicate that the certificate is no longer valid.
   If the certificate is renewed before it expires, the Notifier will
   send a notification with a body containing the new certificate.

It would be nice to state the assumption that there is only one certificate per user at any given time earlier in the document.


6.12.  State Agents and Lists

   The certificate server described in this section which serves
   certificates is a state agent and implementations of the certificate
   server MUST be implemented as a state agent.

Question: which document defines the "state agent" term?

7.6.  Subscriber Generation of SUBSCRIBE Requests

   The UA needs to authenticate with the credential service for these
   operations.  The UA MUST use TLS to directly connect to the server
   acting as the credential service or to a server that is authoritative
   for the domain of the credential service.  The UA MUST NOT connect
   through an intermediate proxy to the credential service.

Last sentence: it would be helpful if the document pointed out
how to achieve this.

7.10.  Notifier Processing of PUBLISH Requests

   If the Subscriber submits a PUBLISH request with no body, this
   revokes the current credentials and causes all subscriptions to the
   credential package to be deactivated as described in the previous
   section.

I think you need an explicit section reference number here, section 7.9 is talking about something else.

In Section 9.5:

   The PKCS#8 in the clients MUST implement PBES2 with a key derivation
   algorithm of PBKDF2 using HMAC with SHA1

I think this needs references to HMAC and SHA1 documents.

   and an encryption algorithm
   of DES-EDE2-CBC-Pad as defined in [RFC2898].  It is RECOMMENDED that
   this profile be used when using PKCS#8.  A different passphrase
   SHOULD be used for the PKCS#8 encryption than is used for server
   authentication.