All your ideas are good, but I think only nature is true random , so if we build something that will use device temperature cpu usage at that instant, and some noise from microphone, then hash them all , then this will be a random number. And again we can choose a system that will announce some perimeters to accept a random number, and all people submit their numbers to him, he then choose the right number and announce, then people will see and verify that if he chosen right number or not.
Please do not try to cook up such an
ad hoc scheme for gathering randomness. The scheme you describe is on its face both inadequate for gathering entropy, and easily influenced by local (physical) or perhaps even network attackers. (A network attacker who can persuade you to visit his website can use Javascript to trivially influence your CPU usage, and thus CPU temperature.)
Worst of all, the scheme you describe requires
trust not only in a central party (“he then choose the right number and announce”), but in
all parties (how do you remotely verify CPU usage and soundcard input?). I see no means whatsoever that “people will see and verify” the result here. What is this thread about? Why not just have your site pick bits off your server’s /dev/random, which nobody else can verify to be fairly obtained? The scheme you describe would provide strictly
less practical security than that, insofar as it is not even a good
local entropy gathering scheme.
If you want a secure network randomness protocol for use on what I presume to be a
provably fair gambling site, then implement a commit-and-reveal protocol as I described upthread, with enhancement of the ideas outlined by gmaxwell for preventing holdup by dishonest participants. This protocol will be
cryptographically secure.Off-topic: If you be interested in gathering entropy from physical sources, I suggest that you read the paper for
Turbid, a high-entropy symbol generator which uses thermodynamic (
not acoustic) noise from the analogue circuits in an ordinary computer soundcard. Proper design of such a thing requires extensive knowledge of both maths and physics. The Turbid author (Dr. John Denker) has both.