[tahoe-dev] SHA-1 broken!

Sandy Harris sandyinchina at gmail.com
Sun May 3 07:59:31 EDT 2009


On Sat, May 2, 2009 at 12:33 PM, Perry E. Metzger <perry at piermont.com> wrote:

> As just one obvious example of a realistic threat, consider that there
> are CAs that will happily sell you certificates that use SHA-1.
>
> Various clever forgery attacks have been used against certs that use
> MD5, see:
>
> http://www.win.tue.nl/hashclash/rogue-ca/
>
> Those attacks can now be extended to SHA-1 pretty easily. It might
> require a bit of compute infrastructure -- say a lot of FPGAs and a
> bunch of cleverness -- to turn out certs quickly, but it can be
> done. Given that there are lots of high value certs out there of this
> form, this is rather dangerous.

Off-the-shelf FPGA-based device that breaks DES by brute force in
about a week, costs 9,000 euros: http://www.copacobana.org/

These are commercially available and programmable. Setting a
few of them up to break SHA-1 certainly would not be trivial,
but it looks feasible.

-- 
Sandy Harris,
Quanzhou, Fujian, China

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