I have an online business where I sell very detailed plans to help people reach a certain goal. My question is this, my information comes as a pdf and I want to know if its possible to have security settings that will not allow it to be opened if it is forwarded to another email address other than the intended party. I am concerned that one person will purchase and then forward to all their friends. Any help here is greatly appreciated.
If you're assembling each PDF by hand, then you could *in theory* apply certificate security, but that would require every customer to get themselves a digital ID and send you their public key - which is unrealistic.
The only realistic option would be to apply digital rights management to the files automatically (on the server before they're downloaded) so that they can be linked to a particular customer, for example via an email address and password; but to do that you'll need to invest in Adobe's LiveCycle server products, and they're far from cheap. The cryptography used in Adobe's DRM is secret, so there are no third-party alternates. The advantage of DRM is that you can revoke access to a specific file if you find out someone's been sharing their password, but remember that if someone can open and print a PDF, they can *always* steal it by printing it to a new file (or if necessary printing it and scanning it back in). It's a balance of how much effort they need to put in to steal it vs. what it costs to buy.