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Old 02-21-2011, 05:17 AM   #2
delphin
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Posts: 434
Karma: 346901
Join Date: Dec 2010
Device: SONY PRS-650
I saw an almost identical complaint in an earlier post, so this has indeed happened to others.

I would guess that it has to do with something screwing up the normal shutdown sequence in the PRS-650's linux OS such that the books individual DRM key gets corrupted or simply unregistered on the reader.

Under Adobe's Adept DRM each book is encrypted using a different randomly generated DRM crypto key and then this key is in turn encrypted using your account key and that result embeded into the book. (the EPUB is a ZIPPED archive with all the book files including this key info)

The advantage of this method is that they don't have to re-encrypt the whole book every time it is sold or lent out from a library, they just have to re-encrypt the short string of bytes that make up the random book-key itself. Since the original key for each book is randomly selected, no one will have clue how to decrypt the books files, unless they can first decrypt the books individualized book-key, so this gives all the needed protection while reducing the servers workload when you download a book.

When you load a book on your PRS-650, if it is DRM protected, the reader knows because these extra key files are present inside the EPUB, so it will use it's registered DRM key to try to decrypt the books individual master key, and if this is successful, it CACHES this book key (along with any lending time-frame limitations related to library titles)

This is as it should be, but if something happens to cause that CACHED key info to be lost or corrupted, then the PRS-650 reader thinks the book has been deauthorized.

I think you have stumbled onto a legitimate software bug.

What SHOULD happen, is that the PRS-650 should simply re-decrypt the books individualized book-key (which is still available in scrambled form inside the EPUB), using your own ADEPT master registration key (which the reader still has filed away), and it should do all of this WITHOUT LOOSING ANYTHING.

You can also run into massive DRM hassles if you have both Adobe Digital Editions and the Sony Reader Library (or a multi-user PC or mac environment with multiple user accounts), and then something happens which causes the various Adobe ADEPT DRM crypto keys to be different.

No one should have to put up with this . . .

- and, as it turns out, you don't

Along with the generally recognized exemption that allows removal of ANY kind of copy-protection which is causing the potential for data loss, the DMCA has a spicific exemption related to the removal of DRM from e-books for any :

Quote:
(6) Literary works distributed in ebook format when all existing ebook editions of the work (including digital text editions made available by authorized entities) contain access controls that prevent the enabling either of the book’s read-aloud function or of screen readers that render the text into a specialized format.
The "specialize format" you are looking for, would I assume be the book WITH YOUR NOTES INTACT.

If the above combination of DRM interacting with a Sony reader bug are preventing you from seeing this "specialized format" , then I suggest you Google "Apprentice Alf's Blog DRM"

Last edited by delphin; 02-21-2011 at 05:36 AM.
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