In message <caaawwbxn_zfk86yfd9myg6-hcnwsw2pmuq6yxwpr6b8v4fo...@mail.gmail.com> , Jimmy Hess writes: > On 7/18/12, Mark Andrews <ma...@isc.org> wrote: > [snip] > > space, you meet the requirements. Toss a coin for each bit. Heads > > =3D 1, tails =3D 0. > Sure... and if someone says they just happened to toss a coin 128 > times, and got "0" all 128 times, therefore legitimately assigned ULA > ID is all zeros, I don't believe them.
Given it is 40 bits not 128 bits the chance of getting all zero/all ones is < 0.000000000001%. > (1 / 2)^128 * ([128 : 128]) > > for =E1 =3D 0.0000000002 > H_0: fair coin > Observation: 128 heads out of 128 flips (or 128 tails out of 128 flips) > > For H_0, Prob given >=3D 128 heads or >=3D tails =3D 2*(1 - Prob(<1= > 28) ) =3D > < 0.000000000000000000000000000000000006% > > Reject H_0. > > > Perhaps the world would be well served if the RFC called for routers to app= > ly > some [very lenient] randomness tests to the sequence of bits proposed > to be configured as a ULA ID.... :) Given there is no such possible test I fail to see how you could expect anyone to implement it. You can't examine a single value to determine if it was randomally choosen or not. Even with multiple values you can't determine if there were randomally or systematically choosen as there are a inifinite number of systems that will produce a randomally choosen sequence. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org
