Which copy protection techniques are available for digital material? [closed]

Question

Suppose a website offers the following resources for premium users:

• PDF Files
• Video Files
• Presentations (e.g. .ppt files)

Which protection techniques are available to prevent (slow down) the user to copy and re-distribute these resources?

Answer 1

PDF - password protection

Video files - DRM (unable to play without license file)

Presentations? No idea.

Most these techniques are also sure techniques to repel normal users from your site.

Answer 2

One good way to protect your material is to make your web site the easiest way to get/view/access your stuff. Note that Apple makes millions of dollars selling MP3's on ITunes that are wholly unprotected, because it is easier for most people to grab them on Itunes than to find them on torrent sites.

Ultimately, you will not be able to prevent a determined user from copying and redistributing your material. The most you can do is try to slow them down. Whatever encryption method you end up using will require a key, and that key will need to end up on your user's computer. Therefore, a determined user will have everything they need to grab the content from you. What you can do is annoy average users enough that they decide it is not worth the trouble. However, there is a fine line to walk between annoying users enough that they pay, and annoying them so much that they leave your site entirely.

Answer 3

Nothing will prevent the user redistributing anything that can be downloaded to the local device. Very few will actually 'slow down' this either. Most all will inconvenience legitimate users completely.

Create compelling content and offer it for a compelling price. Those that see the value will buy it, those that don't see the value would never buy it to begin will so you are really losing anything.

Answer 4

For images, you can put in a watermark (translucent text over the image, but not very noticible, saying something like "© 2010 Me inc.").
Same goes for video files, but in video you could move it to make the process of removing it (which is already extremely hard) harder.
Presentations, I have no clue either, but you could always try having "© 2010 Me inc." at the bottom of all the slides, or on the BG picture.

In truth, there is no way to fully protect your files, but these solutions will do the best to slow down, and possibly stop the user from redistributing your work.