I believe this whole thread about randomness and entropy started with the search for a portable software RNG and the discussion of how to estimate the entropy of spinners. If we accept the above paragraph, then we have to reject spinners as a candidate for such a RNG, for two reasons. First, we have no model of how spinners generate randomness, so we can't estimate their entropy. Second, even if we developed such a model for a particular spinner on a particular OS, the model itself would not be portable because it would likely rely on nonportable assumptions about the OS.

Do we have other candidates for portable software RNGs?

Wei Dai

I think it is best to have a black box that can not be modeled personally. Anyway I am in the middle of putting together a portable RNG that will should consist of nothing more than a photoelectric tube, 9volt battery, and a bit of wiring. It will connect through the serial port. Just put your favorite radioactive substance near it and your set. before people freak out, there are many substances that will produce enough beta particles without killing anyone. In fact you could just use background radiation, but it would take longer. Anyway I'll let you all know how it turns out. -- thecrow@iconn.net "It can't rain all the time" RSA ENCRYPTION IN 3 LINES OF PERL --------------------------------------------------------- #!/bin/perl -sp0777i<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<j]dsj $/=unpack('H*',$_);$_=`echo 16dio\U$k"SK$/SM$n\EsN0p[lN*1 lK[d2%Sa2/d0$^Ixp"|dc`;s/\W//g;$_=pack('H*',/((..)*)$/)