Technological Protection Measures and the Blind

Why Circumvention for the Purposes of Access is Crucial 

A Bookshare Briefing Paper Prepared for the Diplomatic Conference for Visually Impaired Persons

The distributors of digital content often use technological protection measures (TPMs) to discourage the making of unauthorized copies. Unfortunately, these TPMs create collateral damage in the form of disabling or hindering activities that are generally permitted. This is especially acute for accessibility for the blind and disabled, where the TPMs cannot technically distinguish between accessing the content for the making of an illegal copy, or accessing the content to speak it aloud with a synthetic voice or to create a Braille version. This has created the ironic situation where blind people, who because of their disability require access to digital copies, have been effectively locked out of purchasing ebooks for the last decade. Each new content delivery system is eagerly tested by technically oriented blind individuals or the organizations serving them, often to result in disappointment and widespread advice to avoid wasting limited resources on inaccessible content. 

TPMs and Accessibility Challenges 

Here is a short list of the challenges that arise in the interaction between TPMs and accessing digital content:
  1. The digital textual content is presented as an image. In many cases textual content is not delivered as text, but as a digital image of a page of text. This happens frequently with PDFs that are created from page scans. 
  2. The digital textual content is presented as text, but the TPM blocks a screen reader from accessing the text to speak it aloud, or transmitting it to a digital Braille display. 
  3. The digital content is presented as text, but the built-in read-aloud capability is disabled because of ambiguity over audio rights. 
  4. The digital content can be accessed with a read-aloud function, but the read-aloud function is unusable for equal access. Common problems are the inability to go back, pause, spell words (or names) or access footnotes (or be forced to hear all footnotes). 
  5. The digital text can be accessed, but there is impaired access to the structure of the document. It’s allowed in many formats to present the text not in logical reading order, but completely out of order with instructions to the device on how to make the content “look” on the page. 
  6. The digital content can be accessed only on a certain kind of device, and the consumer with the disability doesn’t have that device. [Added by a suggestion from George Kerscher: Similarly, the consumer has a device they have learned to use effectively, but the desired content cannot be moved or used on that device.]  
  7. The content contains images mixed in with the text, and the image content is crucial to using the text. Classic example is a math textbook, where the math equations and diagrams are all presented as images in digital textbooks. So, the student might be able to read only 60% of the relevant content, and have no idea about what the equations say. 
Authorized entities need access to digital content in order to cost-effectively deliver access. The traditional access methods typically involve recreating the content through retyping it, or scanning in the print book and using optical character recognition to obtain the text from the book (typically all graphics are dropped in this process). Since almost all content for the last decade originates as a digital file, using OCR on the scanned page or the PDF image document is a painful reverse engineering process that delivers lower quality access at much greater cost than native full access.

Textbooks in IDEA, the United States K-12 special education law 

The issue of TPMs is the biggest future-proofing question in the Treaty. In some markets, printed books are receding into the past. Amazon now ships more ebooks than print books in the United States. Access to printed books without handling ebooks would be a pyrrhic victory for people with disabilities. This is already apparent in IDEA 2004, the most recent reauthorization of national special education law. A key policy innovation was required all publishers to deliver accessible digital versions of K-12 textbooks that were printed. However, this requirement does not apply to digital-only versions of textbooks, which are already starting to appear. And of course, these digital-only textbooks are being delivered with TPMs that hinder access.

Use of TPMs by Authorized Entities 

The use of TPMs by authorized entities has been presented as somehow invalidating their concerns about TPMs, but this conclusion is logically flawed. Authorized entities are not advocates for the making of illegal copies, or the outlawing of TPMs, or wishing that all information were free. Authorized entities are against TPMs to the extent that they interfere with accessibility. Authorized entities use TPMs for the same reasons as commercial distributors of content: to discourage the making of illegal copies, or to prevent legal copies from reaching unauthorized users. Since authorized entities have a strong obligation to exclusively distribute accessible copies to qualifying people with disabilities, it should come as no surprise that they implement TPMs as part of delivering on that obligation. Authorized entities use both “hard” TPMs such as digital locks that only work with authorized players (i.e., NLS in the U.S.), as well as “soft” TPMs such as fingerprinting (i.e., Bookshare). Authorized entities are, not surprisingly, generally fine with circumvention of their TPMs for the purpose of better accessibility, and are against circumvention of their TPMs for the purpose of making illegal copies (say, for the purposes of distributing their content to people without disabilities). Two examples of this are:
  • Bookshare permits the stripping of fingerprints out of its digital books when used to create master documents for Braille production. Bookshare digital files contain the name of the person or organization that downloaded the digital file, but Bookshare permits Braille production facilities to strip this TPM information out when delivering hardcopy Braille books. Hardcopy Braille is difficult to “pirate,” whereas digital versions can be more easily used to make unauthorized copies. 
  • Authorized entities that distribute audio books often need to remove the TPMs from one flavor of audio book from a different authorized entity, so that they can repackage and distribute that audio book in a different protected audio format that works with the players used by the patrons. 
In both cases, it’s about circumvention for accessibility, not circumvention for breaking the law.


TPMs are blunt and frequently stupid instruments. Many digital content providers have dropped or softened TPMs because they irritate the typical consumer. And these irritations pale next to the denial of access for people with disabilities. The interest of consumers with disabilities and the organizations are best served by the ability to circumvent TPMs to the extent necessary to realize equal access.


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