[Cryptech Tech] ent for rosc entropy in the Xilinx FPGA

Russ Housley housley at vigilsec.com
Tue Dec 9 15:09:18 UTC 2014


> Aloha!
> 
> First results using the ent tool on entropy extracted from the rosc
> entropy source implemented in the Xilinx Spartan-6 device on the Novena.
> this is based on 62 MByte data:
> 
> 
> Entropy = 7.999998 bits per byte.
> 
> Optimum compression would reduce the size
> of this 67121200 byte file by 0 percent.
> 
> Chi square distribution for 67121200 samples is 227.52, and randomly
> would exceed this value 89.14 percent of the times.
> 
> Arithmetic mean value of data bytes is 127.5040 (127.5 = random).
> Monte Carlo value for Pi is 3.141248317 (error 0.01 percent).
> Serial correlation coefficient is 0.000081 (totally uncorrelated = 0.0).
> 
> 
> 
> Not too shabby, it seems to be not totally b0rked.
> 
> I'm doing extraktion of more data. And if anybody wants the current raw
> data to do further analysis just tell me.
> 

I would like to take a look as well.

Russ



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