Last Call Review of draft-ietf-perc-double-10
review-ietf-perc-double-10-genart-lc-housley-2018-10-20-00

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Document: draft-ietf-perc-double-10
Reviewer: Russ Housley
Review Date: 2018-10-20
IETF LC End Date: 2018-11-01 
IESG Telechat date: unknown

Summary: Almost Ready


Major Concerns:

Section 10: Doesn't the IANA registry needs to specify the PRF to be
used with the ciphersuite as well?


Minor Concerns:

Section 3: It would be useful to explain the Master Key before the
reader gets to Section 3.1.

Section 3.1: It is unclear what assistance is provided by the
additional level of indirection:

         PRF_double_n(k_master,x) = PRF_inner_(n/2)(k_master,x) ||
                                    PRF_outer_(n/2)(k_master,x)

         PRF_inner_n(k_master,x)  = PRF_n(inner(k_master),x)
         PRF_outer_n(k_master,x)  = PRF_n(outer(k_master),x)

It could just say:

         PRF_double_n(k_master,x) = PRF_(n/2)(inner(k_master),x) ||
                                    PRF_(n/2)(outer(k_master),x)

Section 4: I suggest:

	If the marker bit is not present, then B MUST be set to zero.

Section 5, 1st paragraph: and endpoint cannot verify confidentiality.


Nits:

The document uses "encryption" and "confidentiality" interchanagably.
Encryption is a mechanism or algorithm.  Confidentiality is a security
service.  While I do not think that the reader will be confused by the
current wording, it would be better to use the terms properly.  In
addition, it is misleading to say:

   ... the receiving endpoint that can encrypt and authenticate ...

because the sending endpoint encrypts, and the recieving endpoints
decrypts.  Also, the receiving endpoints check the authentication tag.

Abstract: s/authenticated encryption with associated data/
           /authenticated encryption with associated data (AEAD)/

Abstract: s/scheme/algorithm/

Section 5.2: s/GCM/AES-GCM/

Section 7: s/HBH/hop-by-hop/

Section 7: s/E2E/end-to-end/

Section 7.1: s/HBH/hop-by-hop/

Section 7.2: The text is redundant.  I suggest "etc" be dropped from
"such as SSRC, SEQ, CSRC, etc"

Section 7.2: s/non primary/non-primary/

Section 7.3: s/HBH/hop-by-hop/

Appendix A: s/HBH/hop-by-hop/

Appendix A: s/E2E/end-to-end/