Re: Accessibility conformance (was RE: Can a publication change over time?)

In the FYI/FWIW category – I will point out that digital signatures on dynamically updatable content aren’t what they seem ☺.

While the technical aspects of verifying that none of the bits have changed (which is important!), it doesn’t guarantee that the content that is display *or* how it interacts with the user, UA or AT, is the same.  Since you have scripts (and CSS) that can vary based on all sorts of criteria – you really never know what you are going to get.

That shouldn't necessary preclude them from consideration (if we decide it would be helpful), but I wanted to note that they aren’t a panacea.

Leonard

From: Avneesh Singh <avneesh.sg@gmail.com>
Date: Thursday, July 27, 2017 at 9:37 AM
To: "White, Jason J" <jjwhite@ets.org>, Romain <rdeltour@gmail.com>, Charles LaPierre <charlesl@benetech.org>
Cc: Garth Conboy <garth@google.com>, Laurent Le Meur <laurent.lemeur@edrlab.org>, Leonard Rosenthol <lrosenth@adobe.com>, "public-publ-wg@w3.org" <public-publ-wg@w3.org>, AUDRAIN LUC <LAUDRAIN@hachette-livre.fr>
Subject: Re: Accessibility conformance (was RE: Can a publication change over time?)


Indeed, this is an existing weakness in web accessibility certification.
A version of webpage is certified, but if web designer updates the page next day, then the new version may be inaccessible. WCAG has been very successful model but it do suffers from such implementation flaws!
[Jason] I take a somewhat different view of WCAG. If a conformance claim is asserted, one of the required components of the claim is the date on which it is made. This is a required component because, indeed, the content may subsequently change, in which case there is no guarantee that it continues to conform, and that the claim is still true. It’s the author’s responsibility to ensure that the content continues to conform, and to update their conformance claim if necessary. I would argue that the conformance claim only holds with respect to the content as it was on the date given in the claim.

Avneesh: Sure, this is conceptually true. But web pages are updated with higher frequency than the publications. This makes it more difficult to ensure that all updates of webpages are certified.

Unfortunately, I think metadata in a publication are amenable to the same problem, since it remains the author’s responsibility to update the metadata as the content is revised. The only solution that comes immediately to mind would be an accessibility conformance assertion which is digitally signed by the party who makes it, and which contains a cryptographically strong hash of the resources to which it applies (e.g., an entire publication). There are no reliable and comprehensive automated tests of accessibility specification conformance, so a weaker requirement than “it’s still the same content” wouldn’t provide a guarantee that it continues to conform.

Avneesh: This can be one of the solution for this issue. Another similar candidate is to maintain a record of the certified publication and its version in the repository of certification agency.
We will discuss all this in accessibility task force calls in future.


With regards
Avneesh

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