Linus' reply on Git and SHA-1 collision
Linus has toned down a lot from a decade ago.<p>&gt; You are _literally_ arguing for the equivalent of &quot;what if a meteorite hit
my plane while it was in flight - maybe I should add three inches of
high-tension armored steel around the plane, so that my passengers would
be protected&quot;.<p>&gt; That&#x27;s not engineering. That&#x27;s five-year-olds discussing building their
imaginary forts (&quot;I want gun-turrets and a mechanical horse one mile high,
and my command center is 5 miles under-ground and totally encased in 5
meters of lead&quot;).<p>&gt; If we want to have any kind of confidence that the hash is reall
yunbreakable, we should make it not just longer than 160 bits, we should
make sure that it&#x27;s two or more hashes, and that they are based on totally
different principles.<p>&gt; 
And we should all digitally sign every single object too, and we should
use 4096-bit PGP keys and unguessable passphrases that are at least 20
words in length. And we should then build a bunker 5 miles underground,
encased in lead, so that somebody cannot flip a few bits with a ray-gun, 
and make us believe that the sha1&#x27;s match when they don&#x27;t. Oh, and we need 
to all wear aluminum propeller beanies to make sure that they don&#x27;t use 
that ray-gun to make us do the modification _outselves_.<p>&gt; So please stop with the theoretical sha1 attacks. It is simply NOT TRUE
that you can generate an object that looks halfway sane and still gets you
the sha1 you want. Even the &quot;breakage&quot; doesn&#x27;t actually do that.  And if
it ever _does_ become true, it will quite possibly be thanks to some
technology that breaks other hashes too.<p>&gt; I worry about accidental hashes, and in 160
bits of good hashing, that just isn&#x27;t an issue.<p><a href="http:&#x2F;&#x2F;www.gelato.unsw.edu.au&#x2F;archives&#x2F;git&#x2F;0504&#x2F;0885.html" rel="nofollow">http:&#x2F;&#x2F;www.gelato.unsw.edu.au&#x2F;archives&#x2F;git&#x2F;0504&#x2F;0885.html</a>