> how to guarantee that nobody hacks in and figures out how to change a few bytes in one paper that is 10years old? You publish hashes of all the documents. It

> how to guarantee that nobody hacks in and figures out how to change a few bytes in one paper that is 10years old? You publish hashes of all the documents. It's trivial to distribute lists of hashes. You can even put them into existing blockchains, which guarantee they won't change.