After a little bit of work I have put together a white noise source (hacked FM reciever, heavily shielded to reduce local EMR bias) and have it jacked into a mic port on one of my machines. I would like to develop of bit of code (oh, horror :) to take bits from the sound card, and bits from /dev/random, and mix them together to get a random number stream.
The noise coming off of the sound card is more beige than white though..
Does anyone know of any papers, articles or whatever on good techniques to remove bias from the audio source? ... If I were doing it, I would probably feed the raw bytes into a stream cipher with feedback, like Sapphire II, and then select every nth byte from
At 09:12 PM 8/5/98 -0400, mgraffam@mhv.net wrote: ... the output stream (just to match the output bit rate to the estimated actual entropy in a conservative fashion and improve the effective avalanche performance of that particular algorithm). This would be faster than a hash like SHA-1. Indeed, you could just use a good mixer, like a CRC or non-cryptographic hash to whiten the noise if speed is an issue. As long as you restrict the output bit rate to less than the actual estimated entropy of the source, you should be alright, provided that your noise source is as random as you think it is. Then again, the truly paranoid may beg to differ. _______ Michael Paul Johnson mpj@ebible.org http://ebible.org http://cryptography.org PO BOX 1151, Longmont CO 80502-1151, USA Jesus Christ is Lord!