From: Michal Suchanek <hramrach@...>
Date: 2009-10-31T06:50:20+09:00
Subject: Re: PDF Viewer

2009/10/29 Rajinder Yadav <devguy.ca@gmail.com>:
> I would like to create an embedded pdf viewer on a website that would
> allow visitors to view online documents but prevent them from
> downloading and saving them. Is there a way to do with Ruby?
>

It's physically impossible, regardless of what various
DRM/DMCA/whatnot activists would like people to believe.

You see the document so you can save it. You can make the actual file
inaccessible but the information contained in the file is presented on
the screen so the user can, at the very least, copy it with a camera.

The rest is just question of inconveniencing the people who would want
to make a permanent copy of the document as well as people who just
want to view it. It's much easier to view documents offline than
online because offline viewing allows for greater resolution
(printouts), internet connection independence (and thus greater
location independence), etc.

There is no copy protection scheme known to me that would protect any
data worth at least a few dollars but many that can inconvenience the
user, to the point that users of legal copies seek unprotected
"pirated" copies to access the data for which they bought a license.

Thanks

Michal