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Encrypted PDF files in IMSLP

Posted: Mon Mar 30, 2009 4:51 pm
by Johann Casper Ferdinand F
IMSLP contains several hundred PDF files that are encrypted and that require an "owner password" for certain actions, such as modifying or extracting pages. See for example IMSLP21765 (Chopin sonata for cello and piano) or IMSLP21874 (a work for piano, 4 hands).

These are public domain scores. I would imagine that these files were obtained from commercial sources and uploaded without any effort being made to unlock them.

There are inexpensive commercially available decryption tools. Does anyone have any experience with these or any open-source alternatives? For example, I would think that ghostscript could probably be modified to do this.

Is it worthwhile for someone to decrypt the affected scores and re-upload them?

Re: Encrypted PDF files in IMSLP

Posted: Mon Mar 30, 2009 4:54 pm
by vinteuil
use pdfsam to merge just the one file. That will decrypt it.

Re: Encrypted PDF files in IMSLP

Posted: Mon Mar 30, 2009 6:21 pm
by daphnis
Perlnerd is correct in using pdfsam (PDF split-and-merge), however as one user noted a while back, there may be a problem with newer versions accomplishing this task, so use version 0.7 (it works for me). As for replacing encrypted files, yes, we really should fix those. It wouldn't take much effort to download them, batch decrypt and reupload. I'd be glad to fix some in immediate need if you'd like.

Re: Encrypted PDF files in IMSLP

Posted: Mon Mar 30, 2009 7:32 pm
by Carolus
Perhaps you should create a category page so that we could have a complete list of these. They are actually fairly easy to decrypt - usually. We do endeavor to have the files for public domain works as unlocked PDFs. Works here that are not public domain, but uploaded by the composer or copyright owner, can of course be encrypted to prevent modification .

Re: Encrypted PDF files in IMSLP

Posted: Mon Mar 30, 2009 7:47 pm
by daphnis
I agree that would be best. Go forward with it, I'll check it out and start replacing files. Keep in mind because the US mirror server is updated only once daily, the updated files may take up to 24 hours to take effect.

Re: Encrypted PDF files in IMSLP

Posted: Mon Mar 30, 2009 7:57 pm
by Johann Casper Ferdinand F
I have updated the list to include copyright status. All but a handful of the affected works are PD, or are licensed using CC-by or CC-by-sa, both of which permit modifications.

Re: Encrypted PDF files in IMSLP

Posted: Tue Mar 31, 2009 5:52 am
by Davydov
I see that at least one typset PDF file I submitted to IMSLP, on the understanding that it would remain locked, is on the list (i.e. the Tchakovsky Research score of the 1812 Overture). If it can't be left as it is, then I'd have to ask that it be deleted.

Re: Encrypted PDF files in IMSLP

Posted: Tue Mar 31, 2009 7:26 am
by Carolus
The typeset should be fine as it is (locked), Davydov. We're only unlocking works that fall in the public domain category. Items tagged N!/N!/N! can remain locked (or unlocked) as their copyright owners wish.

Re: Encrypted PDF files in IMSLP

Posted: Tue Mar 31, 2009 8:18 am
by Johann Casper Ferdinand F
While I agree that we should respect the editor's wishes, the CC-BY-SA license under which the score is available permits derivative uses. If that is contrary to the editor's or publisher's wishes, perhaps they should consider CC-BY-ND instead.

Re: Encrypted PDF files in IMSLP

Posted: Tue Mar 31, 2009 12:03 pm
by Davydov
Johann Casper Ferdinand F wrote:While I agree that we should respect the editor's wishes, the CC-BY-SA license under which the score is available permits derivative uses. If that is contrary to the editor's or publisher's wishes, perhaps they should consider CC-BY-ND instead.
I'm all for JCFF unlocking scanned files of music that's in the Public Domain music, but also grateful for Carolus's assurance that nothing in the N!N!N! category will be affected.

just to explain that the editor of this file has previously found his work republished without the attribution or copyright notices, and this is the reason that it's locked. On uploading it, my understanding was that "derivatives" referred to arrangements or transcriptions of the music, and not alterations to the PDF file itself. Could this point be clarified?

Re: Encrypted PDF files in IMSLP

Posted: Tue Mar 31, 2009 12:27 pm
by Leonard Vertighel
Davydov wrote:just to explain that the editor of this file has previously found his work republished without the attribution or copyright notices, and this is the reason that it's locked. On uploading it, my understanding was that "derivatives" referred to arrangements or transcriptions of the music, and not alterations to the PDF file itself. Could this point be clarified?
I Am Not A Lawyer, however to the best of my knowledge "derivatives" would also include alterations to the file. However, CC-BY-SA requires to maintain proper attribution and the license itself. Redistributing the work or derivatives thereof without attribution or copyright notices is a violation of the license and therefore copyright infringement in the legal sense.

Note also that unlocking a PDF file is trivial (it is not actually encrypted, otherwise one would need a key even to view it). Someone who is willing to commit copyright infringement by removing attribution and copyright notices most likely wouldn't shy away from circumventing the lock as well.