Draft: draft-ietf-perc-private-media-framework

Commentary: Other than revisiting section 3.1.1 and 5.3 after changes to other drafts are complete , these changes either directly , or in - spirit , address all of the feedback / comments . 
 Just a couple of comments inline .
Paragraph (version A):
Endpoint: An RTP flow terminating entity that has possession of E2E
media encryption keys and terminates E2E encryption.  This may
include embedded user conferencing equipment or browsers on
computers, media gateways, MCUs, media recording device and more that
are in the trusted domain for a given deployment.
Paragraph (version B):
Trusted Endpoint: An RTP flow terminating entity that has possession
of E2E media encryption keys and terminates E2E encryption.  This may
include embedded user conferencing equipment or browsers on
computers, media gateways, MCUs, media recording device and more that
are in the trusted domain for a given deployment.
Paragraph (version A):
Key Distributor: An entity that is a logical function which passes
keying material and related information to endpoints and Media
Distributor(s) that is appropriate for each.  The Key Distributor
might be co-resident with another entity trusted with E2E keying
material.
Paragraph (version B):
Key Distributor: An entity that is a logical function which
distributes keying material and related information to trusted
endpoints and Media Distributor(s), only that which is appropriate
for each.  The Key Distributor might be co-resident with another
entity trusted with E2E keying material.
Paragraph (version B):
Call Processing: All tusted endpoints in the conference connect to it
by a call processing dialog, such as with the Focus defined in the
Framework for Conferencing with SIP RFC4353.
Paragraph (version A):
An endpoint's ability to join a conference hosted by a Media
Distributor MUST NOT alone be interpreted as being authorized to have
access to the E2E media encryption keys, as the Media Distributor
does not have the ability to determine whether an endpoint is
authorized.
Paragraph (version A):
A Media Distributor MUST perform its role in properly forwarding
media packets while taking measures to mitigate the adverse effects
of denial of service attacks (refer to attacks), etc, to a level
equal to or better than traditional conferencing (i.e. pre-PERC)
deployments.
Paragraph (version B):
An endpoint's ability to join a conference hosted by a Media
Distributor MUST NOT alone be interpreted as being authorized to have
access to the E2E media encryption keys, as the Media Distributor
does not have the ability to determine whether an endpoint is
authorized.  Trusted endpoint authorization is described in the (add
ref to new signaling draft here).
Paragraph (version B):
A Media Distributor MUST perform its role in properly forwarding
media packets while taking measures to mitigate the adverse effects
of denial of service attacks (refer to attacks), etc, to a level
equal to or better than traditional conferencing (i.e. non-PERC)
deployments.
Paragraph (version A):
An endpoint is considered trusted and will have access to E2E key
information.  While it is possible for an endpoint to be compromised,
subsequently performing in undesired ways, defining endpoint
resistance to compromise is outside the scope of this document.
Endpoints will take measures to mitigate the adverse effects of
denial of service attacks (refer to attacks) from other entities,
including from other endpoints, to a level equal to or better than
traditional conference (i.e., pre-PERC) deployments.
Paragraph (version B):
An endpoint is considered trusted and will have access to E2E key
information.  While it is possible for an endpoint to be compromised,
subsequently performing in undesired ways, defining endpoint
resistance to compromise is outside the scope of this document.
Endpoints will take measures to mitigate the adverse effects of
denial of service attacks (refer to attacks) from other entities,
including from other endpoints, to a level equal to or better than
traditional conference (i.e., non-PERC) deployments.
Paragraph (version A):
As a concrete example, SIP RFC3261 and SDP RFC4566 can be used to
convey the fingerprint information per RFC5763.  An endpoint's SIP
User Agent would send an INVITE message containing SDP for the media
session along with the endpoint's certificate fingerprint, which can
be signed using the procedures described in RFC4474 for the benefit
of forwarding the message to other entities.  Other entities can now
verify the fingerprints match the certificates found in the DTLS-SRTP
connections to find the identity of the far end of the DTLS-SRTP
connection and check that is the authorized entity.
Paragraph (version B):
As a concrete example, SIP RFC3261 and SDP RFC4566 can be used to
convey the fingerprint information per RFC5763.  An endpoint's SIP
User Agent would send an INVITE message containing SDP for the media
session along with the endpoint's certificate fingerprint, which can
be signed using the procedures described in RFC4474 for the benefit
of forwarding the message to other entities by the Focus RFC4353.
Other entities can now verify the fingerprints match the certificates
found in the DTLS-SRTP connections to find the identity of the far
end of the DTLS-SRTP connection and check that is the authorized
entity.
Paragraph (version A):
The Key Distributor is responsible for knowing what endpoints are
allowed in a given conference.  Thus, the Key Distributor and the
Media Distributor will need to know endpoint-to-conference mappings,
which is enabled by exchanging a conference-specific unique
identifier as defined in I-D.jones-perc-dtls-tunnel.  How this unique
identifier is assigned is outside the scope of this document.
Paragraph (version B):
The Key Distributor needs to know what endpoints are to being added
to in a given conference resource.  Thus, the Key Distributor and the
Media Distributor will need to know endpoint-to-conference mappings,
which is enabled by exchanging a conference-specific unique
identifier as defined in I-D.jones-perc-dtls-tunnel.  How this unique
identifier is assigned is outside the scope of this document.