Subject: Results of IETF-conflict review for draft-sheffer-tls-pinning-ticket-11

From: The IESG <[email-masked]>
Date: Mon, 17 Jun 2019 14:34:06 -0700

The IESG has completed a review of draft-sheffer-tls-pinning-ticket-11
consistent with RFC5742.

The IESG has no problem with the publication of 'TLS Server Identity Pinning
with Tickets' <draft-sheffer-tls-pinning-ticket-11.txt> as an Experimental
RFC.

The IESG has concluded that this work is related to IETF work done in the TLS
WG ,but this relationship does not prevent publishing.

Additionally, the IESG requests the following note be added to the document
if it is published:

The cryptographic construction used in this document to derive a
pinning_protection_key from an existing resumption_protection_key (e.g., one
that is shared across a cluster of servers authoritative for the same domain)
reuses the same long-term cryptographic key for both bulk encryption (of TLS
session tickets) and as the PRK input to HMAC [RFC2104] via the HKDF-Expand()
[RFC5689] construction.  This reuse of key material without an intermediate
derivation step has not undergone extensive cryptanalysis and may introduce
unforseen weaknesses for both the original session-ticket encryption usage
[RFC5077] and the new usage proposed in this document.

The IESG would also like the Independent Submissions Editor to review the
comments in the datatracker related to this document and determine whether or
not they merit incorporation into the document. Comments may exist in both
the ballot and the history log.

The IESG review is documented at:
https://datatracker.ietf.org/doc/conflict-review-sheffer-tls-pinning-ticket/

A URL of the reviewed Internet Draft is:
https://datatracker.ietf.org/doc/draft-sheffer-tls-pinning-ticket/

The process for such documents is described at
https://www.rfc-editor.org/indsubs.html

Thank you,

The IESG Secretary