I have no idea on how to solve the general problem of DRM
removal. Depending on where you live, it may actually be very much
against the law.
Furthermore, as I said in a comment, DAISY books come in different
formats, independently of DRM, depending on whether they contain
speech, text to be speech synthesized or both. I think the most common
standard is DAISY 2.02, which (from what I understand) contains only
speech, but I am no expert on DAISY which I never heard of before.
I would expect that the type of DRM used is dependent on the standard,
and may also depend on the publisher, or on the brand of the
reader. Thus there may be no universal answer to your question.
For a specific book, it may be useful to know the standard used, and
probably the kind of reader, or the kind of DRM.
Now, you tell in a comment, which you should (probably) integrate to
your question to better focus it, that you are interested in the book
I still do not know how to remove the DRM technically, and, if I knew,
answering you could get me into significant trouble. The archive.org
site is a wonderful site (I mean that), which by its very purpose is probably not too friendly to
DRM, but there is nothing they can do when a book is still under
To know more , I unzipped the file, which I hope you did too. This
gives you a bunch of files, including a file README_encrypted.txt
which says it uses a key from the National Library Service, and point
to the files http://openlibrary.org/help/faq/accessing#what-is-daisy
and https://nlsbard.loc.gov/ for more explanation.
They explain that the program (for modern books, hence under
copyright) is reserved to residents of the USA and
American citizens living overseas. I am not quite sure how they do
that legally, though they clearly enforce that with the DRM key.
Some countries do have laws that make a copyright exception to the
benefit of disabled people within the country. I am not sure whether
that is the case in the USA, but it would be the simplest
explanation. However it does not explain giving access to American
citizens in other countries, since international treaties give the USA
jurisdiction on copyright only within the USA.
Now if your country of residence has a similar law (free access for
disabled people) then it is possible that the National Library Service
would accept to give you a key to be used from your country, since
that would not raise any copyright infringement issue (though they might want to have an official agreement between countries). Maybe you
can try to discuss that with the people at email@example.com, or the people
at NLS. And you shold check the copyright law in your own country
regarding exceptions for disabled people.
This is just my best understanding, and all the suggestions I can give to solve your problem, and I am not a lawyer.