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Re: PDF Files and Copyright

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 3 Sep 2001 20:48:55 -0400 (EDT)
To: Miraz Jordan <miraz@firstbite.co.nz>
cc: Graham Oliver <graham_oliver@yahoo.com>, <w3c-wai-ig@w3.org>
Message-ID: <Pine.LNX.4.30.0109032046110.25226-100000@tux.w3.org>
HTML (or almost anything) can be signed so that it is possible to know if it
has been edited.

Acrobat reader makes it a little more difficult to copy material than HTML,
becuase HTML can be read in any software. But it is perfectly possible to
require a password to read the HTML in the first place. It is margnially more
difficult to copy and paste PDF content that has been secured than it is
HTML, but only marginally. And of course it is important that people who need
access for their screenredaer or the like can have it, so Adobe have a
mechanism for allowing this.



On Tue, 4 Sep 2001, Miraz Jordan wrote:

  At 21:47 +0100 03/09/2001, Graham Oliver wrote:
  >One of the arguments put forward for using PDF files
  >on web sites is that the content is not 'editable' by
  >the web site visitor, whereas an HTML page is easily
  >edited by the web site visitor.
  >So 'We use PDF files because our information is
  >copyrighted and we want to protect it' is an argument
  >put forward.
  >Is this right?
  >What are the alternative perspectives?

  At 16:59 -0400 03/09/2001, David Poehlman wrote:
  >If I have a pdf creation tool, I can often edit the document.

  I have just bought Adobe Acrobat but don't yet know my way around it
  thoroughly. It's true that I can use it to edit PDFs. It's also true
  that I can "digitally sign" the document and that this signature can
  be verified and alert the enquirer to changes having been made since
  it was signed.

  I can also secure the document to require a password to be able to
  open it and / or a password to be able to edit it.

  I think these features would allow me as a provider of content to
  feel reasonably assured that I can protect my work, and if necessary,
  prove that it had been edited since I created it.

  A plain old HTML file though could easily be edited by another party
  and then supplied via email or another medium to someone else.
  Interestingly enough, another list I'm on has just had a big
  discussion about the concept and methods of attempting to secure the
  HTML. The general consensus is not to try as it can't be done.
  Attempts can merely delay anyone trying to get at the code.



Charles McCathieNevile    http://www.w3.org/People/Charles  phone: +61 409 134 136
W3C Web Accessibility Initiative     http://www.w3.org/WAI    fax: +1 617 258 5999
Location: 21 Mitchell street FOOTSCRAY Vic 3011, Australia
(or W3C INRIA, Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex, France)
Received on Monday, 3 September 2001 20:48:57 UTC

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