They&#x27;ve even been understood for years too...<p>For example, today I participated in a demonstration of trustlessly, privately, and securely selling information (a 16x16 sudoku solution) via Bitcoin:<p><a href="https:&#x2F;&#x2F;bitcoincore.org&#x2F;en&#x2F;2016&#x2F;02&#x2F;26&#x2F;zero-knowledge-contingent-payments-announcement&#x2F;" rel="nofollow">https:&#x2F;&#x2F;bitcoincore.org&#x2F;en&#x2F;2016&#x2F;02&#x2F;26&#x2F;zero-knowledge-conting...</a><p>(But you probably won&#x27;t read about it on HN; no profit in promoting it. &lt;&#x2F;cynic&gt;)