Heres the article i normally link to when this comes up: <a href="http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;4014090&#x2F;is-it-safe-to-ignore-the-possibility-of-sha-collisions-in-practice" rel="nofollow">http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;4014090&#x2F;is-it-safe-to-ign...</a><p>Its generally considered safe to ignore, there are no known sha256 collisions, and most people are fairly confident they wont see one for quite some time.