Are you sure it was the whitepaper? He published the title of a headline in the first block that was made (can't remember what it said now) if you open the first blk file bitcoin core downloads you can see what he wrote.

If you're after a way of storing data there are some solutions such as storj that link you up with people renting out hard drive space...

You can have other solutions as well such as only checking message that are from, to or contain a certain address... But you'd also have to check no one sabatages that so it might be better to just look at transactions FROM if you did try to go through with something like this.