I don't think this is a good idea since many of the noises that surround the average person is fairly non-random. Be it the hum of a car engine or even static o

I don't think this is a good idea since many of the noises that surround the average person is fairly non-random. Be it the hum of a car engine or even static of a white noise generator. There's too much structure in the machines and living things around people. Plus, atmospheric changes can change or offset noises in such a way that most people don't notice but it would throw off any sufficiently sensitive hardware which would be harder still to verify against.