how to make the contents of a file disappear after x numbers of days or at date

[user1]

> Why not tell us what you are actually trying to achieve? Maybe if you
> told us the actual problem, we could suggest other ways to solve it.

Lets say I want to send a picture to a person - then I do not want the 
person to copy it and use it for "some purpose" - the person is not an 
expert, so after a day in his posession the contents of the image 
disappears - same idea with a text file?

Just an idea I got to day when walking my tour in the woods *smile*

I am constantly thinking of linux and new ideas in my subconsciouness.

In a way a kind of "virus" but its only purpose is to remove the contents 
of the very file of mine, either on my computer or on somebody elses.

Life is change and developement *philosophical*