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

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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: