#!/bin/bash

# poor-man's quantum photon detector randomizer
# ~1kb/s
# over a test of a thousand time, global entropy was equal to 7.99/8 and passed nearly all Dieharder tests, as well as FIPS 140-2
# however, sigma, mean and chi-square stats aren't too much enthusiastic
# overall, the result is pretty impressive, but of course, don't use it in production :)

DEVICE=/dev/video0
# for external cameras should be /dev/video1
FORMAT=image2pipe
# fps-based image sequence from demuxer through pipe, format is automatically determined, as well as FPS and resolution
# TODO force PNG format?
TIMING=0.1
# such timing is considered more or less practical for RNG based on my tests

while true
do
        ffmpeg -i $DEVICE -f $FORMAT -t $TIMING - 2> /dev/null | sha512sum | cut -d ' ' -f 1
done

# in the end when pressing Ctrl+C there will be repetitions