[Cryptography] Photon beam splitters for "true" random number generation ?

Bill Frantz frantz at pwpconsult.com
Wed Dec 23 16:49:59 EST 2015

On 12/22/15 at 4:45 PM, ron at flownet.com (Ron Garret) wrote:

>On Dec 22, 2015, at 1:45 PM, Bill Frantz <frantz at pwpconsult.com> wrote:
>>On 12/21/15 at 7:26 PM, mitch at niftyegg.com (Tom Mitchell) wrote:
>>I wanted to use random chance in a knitting pattern I was building, so I tossed a coin. I quickly gave
>up on the coin when I discovered that my tosses were quite biased. I moved to using /dev/random.
>>Even with a reasonably unbiased item like a coin, getting random tosses can be hard.
>I’m honestly not sure if this discussion is serious or not 
>because rolling dice is so obviously silly (and quibbling over 
>the number of sides is even sillier).  But on the off chance 
>that I’m not just being punked, here are some better ways of 
>generating entropy for yourself:
>Take a picture with your cell phone and take the SHA512 hash of 
>the resulting image file.  That will give you 4096 bits of high 
>quality entropy.  If you want to be extra paranoid, find an old 
>TV, tune it to a non-existant channel and take a picture of the screen.
>Alternatively, make an audio recording of a radio tuned to an 
>inactive FM channel (or of yourself saying “Shhhh…” for a 
>couple of seconds) and take the SHA512 hash of the resulting 
>audio file.
>Much, much faster than rolling dice or flipping coins, and much more high quality entropy too.

To some extent, this is a serious discussion. Flipping coins and 
rolling dice has often been mentioned as a good source of random 
values. I flipped a coin because for the small number of random 
choices I needed, it was a lot faster than writing a program. 
When I discovered my flipping technique was biasing the output, 
I broke down and wrote a program.

I will point out that the Super Bowl, and all professional US 
football games start with a coin flip. The procedures they use 
are designed to minimize issues of poor flips: (1) The other 
team calls the flip while the coin is in the air. (2) The 
reverse of the outcome is used at start of the 2nd half. But 
there are still some small advantages to winning the flip.

Cheers - Bill

Bill Frantz        |"Web security is like medicine - trying to 
do good for
408-356-8506       |an evolved body of kludges" - Mark Miller
www.pwpconsult.com |

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