[greenstone-users] RE: how to restrict documents

From Will Farrell
DateMon, 21 Apr 2003 12:37:03 -0500
Subject [greenstone-users] RE: how to restrict documents
In-Reply-To (20030421111247-16414-qmail-webmail30-rediffmail-com)
G'day (again) Deepak,

>>in the course of building collection of PDF and word documents i
>>feel need of some technique to restict the user [reader] to print
>>the PDF documents or to restict to download of the documents. I
>>want to give the read access of PDF documents to the
>>readers[users] rather than downloading it.

>You can encrypt your PDFs in a way which allows the user (who doesn't
>have the password) to view and save the document, but not to copy from
>or print the document. The saved document cannot be copied or printed
>either. A number of free (and $$$) pdf utilities allow you to do this.
>I can't remember which utility I use, but I'll mail a follow up when I
>do remember.

Now I do remember: Its called PSP (Pretty Safe PDF). PSP allows you to
modify the security aspects of PDF documents on the fly (we do this after
the documents have been included in the collection, otherwise their content
would not be extracted in the index process.) The software is free for
development purposes, and costs $400 (I think) for one server licence.
PSP has APIs for C, C++, Java and PHP (+ActiveX / COM stuff).
The site is http://www.pdflib.com

If you're not a programmer then don't worry - this process could be done
'by hand' (ie. once the documents have been included in the collection
manually write a copy-protected version of the same document in its place.)
using other more user friendly software.

I've never used it, but Signature995 from http://www.signature995.com/ might
be the go. It's free (annoy-ware) or $9.95 for the full version. It looks
like it's only good for Windows (what a shame - anyone know of a good
open source Unix/Linux PDF enryption tool?). It can be used via its graphic
interface or the command line (that means someone could write a batch file
for
you to automatically encrypt your PDFs once they're in a collection).

Hope this helps,

Will.

> G'day Deepak,
>
>>in the course of building collection of PDF and word documents i
>>feel need of some technique to restict the user [reader] to print
>>the PDF documents or to restict to download of the documents. I
>>want to give the read access of PDF documents to the
>>readers[users] rather than downloading it.
>
> As far as I am aware it is impossible to stop users downloading what
> they can see in their browser without using a specialised Java applet.
>
> I'm not so sure about Word documents, but I can help a little with
> PDFs...
>
> You can encrypt your PDFs in a way which allows the user (who doesn't
> have the password) to view and save the document, but not to copy from
> or print the document. The saved document cannot be copied or printed
> either. A number of free (and $$$) pdf utilities allow you to do this. I
> can't remember which utility I use, but I'll mail a follow up when I do
> remember.
>
> There is another (not so nice but more secure) option. PHParchitect
> magazine had a free downloadable article in January about building a
> "Web-based PDF Viewer". It basically creates images of the PDF page the
> user wants to view on the fly. The user doesn't access the PDF directly.
> The good news is that hardly anyone will want to copy then OCR a pile
> of images - the bad news is that this will use up your bandwidth and
> server resources if you have many users browsing PDFs at the same time.
> The link is: http://www.phparch.com/issuedata/2003/jan/sample.php
>
> Hope this helps,
>
> Will.