My first thought is how does it handle SHA hash collisions? Googling for it took me back to HN: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=9322489" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=9322489</a> AFAICT it&#x27;s not yet resolved.