I'm looking for a software that will allow me to distribute files on a USB stick (or CD/DVD also a possibility) that will lock the information after a determinated number of days.
It would be nice if it also prevented the copy of the files.
The solution doesn't have to be perfect, just functional enough that will deter most people.
Require online access, check against a server that looks up the key that's on the drive and disallows it after the trial period is up. If the server says it's still valid you decrypt the file and render it to a canvas internally so what is displayed to the user can't be cut & pasted. They could still take screenshots, though.
Try using GPG to encrypt the files, with a time-limited key. The encrypted files can be copied, but they're essentially useless without the key. After the provided key expires, the recipient can't open the files any more.
