Re: PDF is blocked for printing, etc. OK for acroread (it behaves as expected), but KPDF allows me to print it, even if it is protected! Why?

[Gunnar Wolf <gwolf@gwolf.org>]

Russ Allbery dijo [Mon, Apr 19, 2010 at 02:14:21PM -0700]:
> I think people are not understanding why users use this feature in some
> environments.
> 
> Yes, sometimes it's a misguided attempt at DRM, but I've more often seen
> it inside a workplace as defense in depth against *mistakes*.  One might,
> for instance, mark a document as not printable because it contains social
> security numbers and salary information and it's corporate policy not to
> create hard copies of the document beause of the risk of exposure of
> personal information that might put the company at legal risk.
> 
> That's not to say that Debian PDF viewers should support this the way that
> Acrobat does, but for that use case, the desired UI is probably something
> like a dialog box that pops up and says that the document author has
> marked this PDF as not printable and asking the user if they're sure they
> want to override.  For this use case, such a warning would probably serve
> the same purpose.

The reasons not to want a document printed are quite easy to
understand, but the mechanism is flawed. Given the setting you
mention, you can just slap a red banner stating "Confidential, do not
print". If it is on a corporate setting, just state it as a policy -
and if somebody fails to comply with the policy, there should be
sanctions.

Of course, somebody interested in printing the file will do it. Either
by his own means or, like my users, by mailing the "techie" the
document asking him to unprotect it. Or by sticking it on a USB key
and taking it off-site to a location they can freely tinker with.

As I said on my previous mail: If you don't want it to be printed,
distribute in a way that makes it hard to be useful when
printed. Don't you trust somebody with social security numbers and
salary information? Don't give it to them.

-- 
Gunnar Wolf • gwolf@gwolf.org • (+52-55)5623-0154 / 1451-2244