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From: "David Symonds" <dsymonds@gmail.com>
To: "J.C. Pizarro" <jcpiza@gmail.com>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>, git@vger.kernel.org
Subject: Re: NIST's policy: sha-1 until 2010, after 2010 sha-2.
Date: Sat, 29 Dec 2007 15:45:35 +1100	[thread overview]
Message-ID: <ee77f5c20712282045ha230f42n3e68477229deb199@mail.gmail.com> (raw)
In-Reply-To: <998d0e4a0712282027y6e625141jcef90bd38fb83b75@mail.gmail.com>

On Dec 29, 2007 3:27 PM, J.C. Pizarro <jcpiza@gmail.com> wrote:
> Dear Linus Torvalds,
>
> What do you think to do when your git has to change from SHA-1 to SHA-2
>   because of the weaker collision-resistance of SHA-1 in the next years?
>
>     (e.g. from an damn developer trying to commit a collisioned-SHA-1 file)

It's a non-issue. The closest-to-practical attack method on SHA-1 is a
collision-finding attack, not a second pre-image attack, which means
you can find two messages with the same hash. As far as I know,
there's no significant weakness known for finding a pre-image, which
would be the most practical way of weakening Git's "security" via
SHA-1 substitution.

Regardless, the use of SHA-1 in Git isn't primarily for security,
though it is a nice side-effect. The SHA-1 is there for reliability in
addressing and as a good hash.


Dave.

  reply	other threads:[~2007-12-29  4:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-29  4:27 NIST's policy: sha-1 until 2010, after 2010 sha-2 J.C. Pizarro
2007-12-29  4:45 ` David Symonds [this message]
2007-12-29  5:07   ` David Brown

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