Last Call Review of draft-ietf-tls-ecdhe-psk-aead-03
review-ietf-tls-ecdhe-psk-aead-03-genart-lc-romascanu-2017-05-15-00

Request Review of draft-ietf-tls-ecdhe-psk-aead
Requested rev. no specific revision (document currently at 05)
Type Last Call Review
Team General Area Review Team (Gen-ART) (genart)
Deadline 2017-05-18
Requested 2017-05-04
Other Reviews Secdir Last Call review of -03 by Benjamin Kaduk (diff)
Genart Telechat review of -04 by Dan Romascanu (diff)
Review State Completed
Reviewer Dan Romascanu
Review review-ietf-tls-ecdhe-psk-aead-03-genart-lc-romascanu-2017-05-15
Posted at https://mailarchive.ietf.org/arch/msg/gen-art/wa0fu_idf_O7msdKCpkt--qwf48
Reviewed rev. 03 (document currently at 05)
Review result Ready with Issues
Last updated 2017-05-15

Review
review-ietf-tls-ecdhe-psk-aead-03-genart-lc-romascanu-2017-05-15

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

For more information, please see the FAQ at

<https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.

Document: draft-ietf-tls-ecdhe-psk-aead-??
Reviewer: Dan Romascanu
Review Date: 2017-05-15
IETF LC End Date: 2017-05-18
IESG Telechat date: 2017-05-25

Summary:

This is a straight-forward and clear document that defines several new cipher suites for the Transport Layer Security (TLS) protocol version 1.2 and higher, based on the Ephemeral Elliptic Curve Diffie-Hellman with Pre-Shared Key (ECDHE_PSK) key exchange together with the Authenticated Encryption with Associated Data (AEAD) algorithms AES-GCM and AES-CCM. The document is well written and I appreciate the effort to clarify in the Introduction the context, what was missing, and why the document is necessary. The document is Ready, there is one issue about support for TLS version 1.3 and higher that may need some text clarification. 

Major issues:

Minor issues:

Section 4 ('Applicable TLS Versions') describes in details how the cipher suites defined in the document make use of the authenticated encryption with additional data (AEAD) defined in TLS 1.2 [RFC5246] and DTLS 1.2 [RFC6347]. About TLS 1.3 it just says: 

' TLS 1.3 and above version, negotiate and support these cipher suites in a different way.'

This may raise some concerns as 'in a different way' is ambiguous, especially compared to the details included for TLS 1.2. Moreover, TLS 1.3 is still work-in-progress, and I believe that this document when approved needs to wait for TLS 1.3 to be approved for publication. Will anything change, or need to be added? Some better clarification text would help IMO. 

Nits/editorial comments: