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

Ron Garret ron at flownet.com
Tue Dec 22 19:45:22 EST 2015

```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:
>
>> On Fri, Dec 18, 2015 at 6:51 AM, Patrick Chkoreff <patrick at rayservers.net>
>> wrote:
>> ...
>>> Right, or use a set of 16-sided dice.  I bought some a few years ago.
>>>
>>
>> Why 16-side?
>> N-sides allows base N and conversion to any other interesting base would be
>> easy.
>> The only constraint is the dice needs to have sufficient symmetry that any
>> outcome
>> is equal to any other OR the distribution is well enough understood that
>> can be noted and compensated for (coin lands on an edge).
>
> 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.

rg

```