Tony Nelson wrote: > On 10-01-07 12:40:02, Roberto Ragusa wrote: >> Luca wrote: >>> Hi all, >>> if I simply write to /dev/random, will that increase the entropy >>> of my system? (I'm assuming that the data I'm writing are random >>> and that somehow I got them). >> Wikipedia says so. >> >> My tests say no. >> >> In particular this brutal approach does not increase the entropy >> cat /dev/urandom >/dev/random >> (it is stupid to do that, I know, but it's just a test) > ... > > `man 4 random` says that the current entropy can be read and written > from /dev/urandom, not /dev/random. This is used to preserver entropy > across reboots. That's true. But as far as I can see neither writing to random nor to urandom will increase the entropy availability. After checking the sources of rngd, I found it uses a specific ioctl: ioctl(random_fd, RNDADDENTROPY, &entropy); So I think Luca can inject entropy by using the same ioctl in his own application, or by using rngd in some way (you can tell it where to take entropy from). -- Roberto Ragusa mail at robertoragusa.it -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
