Brian Atkins, <email@example.com>, writes:
> Maybe related: there is an ad in the latest Wired for csafe.com > > Purports to allow for safe posting of copyrighted images, plus > a purchase option. Requires user to download an ActiveX or > Netscape plugin.
>From an article linked from their web site:
: The first application based on that technology, PixSafe, due out this
: summer, will guard graphics. Surfers attempting to save a protected
: picture will find the "save as..." function in their browsers disabled
: when they try to save the graphic, and a pop-up window will warn that
: the image is protected by PixSafe. Those who try to save the graphic
: with a screen-capture function -- software which saves any part of,
: or the whole screen, by simply replicating it pixel by pixel instead of
: copying the whole file -- will find that in the reproduction, the
: graphic is replaced by a big "X."
This is an example of what Kelsey and Schneier were warning against in that article I referenced. It's very difficult to make schemes like this secure. What if you're running Windows in an emulator box, like VirtualPC on the Mac? The encapsulated OS doesn't know that its display is under the control of another OS which can capture graphics or do whatever else it likes. In general, if you are displaying images or sounds to the user, there will usually be a way to make copies.