On 13 January 2012 16:21, Steffen Hoffmann <hoff...@web.de> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Am 13.01.2012 10:48, wrote Roman Yeryomin: >> The best noise source would probably be radial mse parameter which >> will include radio noise and circuit noise. So, potentially, it's even >> better than hardware random generators (which take only circuit >> noise). > > Silently watching here for a long time now. But I can't resist any longer. > > What you tell here is essentially a use case for every IT security > conscious person, that i.e. would not switch from wire to wlan devices > for good measure. Anyone could profit from a high output random number > generator. Even using the wlan nic for /dev/urandom exclusively would be > great. > > You wonder why? I remember waiting for more than 6 hours to fill a > 300+GB hard disc with random bytes when initializing a LUKS partition. > CPU was at max, any I/O towards the disc certainly not. If this is > really that good, and it seems like that, I don't know, why it hasn't > been done before. I would see this implemented rather sooner than later > and pushed upstream to be used by anyone on desktop and servers too. > > Keep-up the good, ambitious work. >
I took a quick glance at wireless drivers and few datasheets I've found in the Internet. As far as I understand the main problem here is lack of good information from the chip. Noise level which is available (on probably all wifi chips) seems to be 0.5 dbm precise at best, so it may change very rarely. Although, as noted, Pars Mutaf (http://www.freewebs.com/pmutaf/iwrandom.html) already did this, it may not be enough to be TRNG. There are PHY error counters (as I understand usually they are available) for OFDM and CCK modulation errors. But, again, they may not change (as I understand it) if you are alone in the air. I'm going to play with phy counters and test it in usual and wifi silent environment and see how good is that. BTW, seems that there are wifi cards which already give ready to use random bits (see CONFIG_CARL9170_HWRNG). It would be interesting to see how good is the distribution of random bits generated by those cards. Regards, Roman _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel
