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.
In a reply that was posted here, someone linked a thread which links this url
http://www.righto.com/2014/02/ascii-bernanke-wikileaks-photographs.html?m=1 that outlines a few examples of things being stored on bitcoin's blockchain. I am not interested in using other technologies or blockchains, just what is available within bitcoins limitations. Ideally I would want at most maybe 2 or 3 KB of storage per transaction, but if I was absolutely limited to 20 bytes I could still do a limited version of what I want to do.