SHA1 collisions proven possisble

Thu Mar 2 05:45:21 UTC 2017

On 3/1/2017 10:50 PM, James DeVincentis via NANOG wrote:
> Realistically any hash function *will* have collisions when two items are specifically crafted to collide after expending insane amounts of computing power, money, and… i wonder how much in power they burned for this little stunt.

Easy enough to estimate.

A dual-socket server with 2 X5675 CPUs (12 cores total) draws about 225W 
under full load, or about 18.75W per core.

0.01875 kW * 8766 h/y * 6500 y = about 1,070,000 kWh

For the GPU side, an NVIDIA Tesla K80 GPU accelerator draws 300W at full 
load.

0.3 kW * 8766 h/y * 110 y = about 290,000 kWh.

So the total calculation consumed about 1.36M kWh.

A quick Google search tells me the US national average industrial rate 
for electricity is $0.0667/kWh, for a cost of $90,712. That's not 
counting AC-DC conversion loss, or the power to run the cooling.  Or the 
cost of the hardware, though it's fair to assume that in Google's case 
they didn't have to buy any new hardware just for this.