Draft: draft-ietf-tls-external-psk-guidance

Commentary: The comment about how there are no guidelines about PSKs like there are about generating passwords seemed like a statement of the motivation for this draft , so I moved it to the introduction . ( I was going to add a reference for the statement , but I could n't figure out how to get the citation to compile correctly . This was the document I was going to cite , in case you think it needs it : )
Paragraph (version A):
This document provides usage guidance for external Pre-Shared Keys
(PSKs) in TLS.  It lists TLS security properties provided by PSKs
under certain assumptions and demonstrates how violations of these
assumptions lead to attacks.  This document also discusses PSK use
cases, provisioning processes, and TLS stack implementation support
in the context of these assumptions.  It provides advice for
applications in various use cases to help meet these assumptions.
Paragraph (version B):
There are many resources that provide guidance for password
generation and verification aimed towards improving security.
However, there is no such equivalent for external Pre-Shared Keys
(PSKs) in TLS.  This document aims to reduce that gap.  It lists TLS
security properties provided by PSKs under certain assumptions and
demonstrates how violations of these assumptions lead to attacks.
This document also discusses PSK use cases, provisioning processes,
and TLS stack implementation support in the context of these
assumptions.  It provides advice for applications in various use
cases to help meet these assumptions.
Paragraph (version A):
Pre-shared Key (PSK) ciphersuites were first specified for TLS in
2005.  Now, PSK is an integral part of the TLS version 1.3
specification RFC8446.  TLS 1.3 also uses PSKs for session
resumption.  It distinguishes these resumption PSKs from external
PSKs which have been provisioned out-of-band (OOB).  Below, we list
some example use-cases where pair-wise external PSKs (i.e., external
PSKs that are shared between only one server and one client) have
been used for authentication in TLS.
Paragraph (version B):
PSK ciphersuites were first specified for TLS in 2005.  Now, PSKs are
an integral part of the TLS version 1.3 specification RFC8446.  TLS
resumption PSKs from external PSKs which have been provisioned out-
of-band (OOB).  Below, we list some example use-cases where pair-wise
external PSKs (i.e., external PSKs that are shared between only one
server and one client) have been used for authentication in TLS.
Paragraph (version A):
Many industrial protocols assume that PSKs are distributed and
assigned manually via one of the following approaches: typing the
PSK into the devices, or via web server masks (using a Trust On
First Use (TOFU) approach with a device completely unprotected
before the first login did take place).  Many devices have very
limited UI.  For example, they may only have a numeric keypad or
even less number of buttons.  When the TOFU approach is not
suitable, entering the key would require typing it on a
constrained UI.  Moreover, PSK production lacks guidance unlike
user passwords.
Paragraph (version B):
Many industrial protocols assume that PSKs are distributed and
assigned manually via one of the following approaches: typing the
PSK into the devices, or via web server masks (using a Trust On
First Use (TOFU) approach with a device completely unprotected
before the first login did take place).  Many devices have very
limited UI.  For example, they may only have a numeric keypad or
even less number of buttons.  When the TOFU approach is not
suitable, entering the key would require typing it on a
constrained UI.