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Hi, mnot has already heard the following concerns from us at CDT about
this spec, but we want to make sure that these are part of the IETF
last call comment record.
* The "Safe" preference is not only a preference but a signal. It
signals user vulnerability; when activated, the header would signal
a user's potentially vulnerable status not only to site operators
who intend to reply in good faith, but to those that will operate in
bad faith and also to every intermediary on-path that could read the
preference request.
Details about an Internet user's vulnerabilities should be treated
as sensitive information. A broadcast signal that advertises a
user's content preferences or restrictions can signal her youth,
cognitive ability, relative media illiteracy, technological
inexperience, or another potential vulnerable status. Because of
the risk that this information could be used to exploit immature or
inexperienced users, CDT generally cautions against widespread
identification of user vulnerability. Obviously, sending such a
preference inside an encrypted connection removes concerns about
on-path observers, but not the more general concern with bad faith
endpoints or other embedded endpoints that may have other interests
(e.g., advertisers on a service may use this signal to profile
vulnerable populations).
* Further, the ability for other intermediaries with access to the
request stream to insert the preference, potentially without notice
to the user, means that users may not even be aware that they are
broadcasting potentially sensitive information about themselves,
thus limiting their ability to take self-protective measures against
potential abuse.
* As many of the comments in Last Call have identified, "Safe" content
in this specification is undefined. Because the proposal
(necessarily) lacks a definition of "safe", it is unlikely to be
useful to parents/guardians/users. The lack of definition will
produce diverse and conflicting interpretations from content hosts
and providers, which can mislead users and their guardians, and may
invite abuse and confusion.
The absence of guidance to websites wishing to participate in "safe"
content delivery will lead to varied and sometimes contradictory
results. This could sow confusion and potential conflict among
participating platforms and website operators, and undermine the
utility of the specification.
Moreover, users and their parents will have diverse expectations
about "safe" content. These expectations will vary considerably
with users' age, as well as parent/guardians' cultural backgrounds.
Without a common understanding of what qualifies as "safe" content,
the expectations of users and their parent/guardians are likely to
be frustrated. Of course, it is far outside the scope of a
technical specification to define a content-label like "safe". But
because a standardized definition of "safe" content is unattainable,
the specification will have limited use as a tool for empowering
parents to regulate and guide their children's Internet use.
- --
Joseph Lorenzo Hall
Chief Technologist
Center for Democracy & Technology
1634 I ST NW STE 1100
Washington DC 20006-4011
(p) 202-407-8825
(f) 202-637-0968
joe(_at_)cdt(_dot_)org
PGP: https://josephhall.org/gpg-key
fingerprint: 3CA2 8D7B 9F6D DBD3 4B10 1607 5F86 6987 40A9 A871
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