On Sun, Jan 24, 2010 at 05:56:27PM +0100, Heinz Diehl wrote: > On 24.01.2010, Rick Moritz wrote: > > > Once the entropy pool is exhausted, yes. Because then the randomness is no longer actual randomness, but pseudo-randomness, > > Yes, urandom is a PRGN. > > > and can be predicted if you have the random seed available. > > Thanks for pointing this out again! So I don't have to worry, nobody will > get hands on my random seed ever. The time I generated the master key to > my partitions is long gone, and so is the random seed. If your system had some decent interaction (say at least 50 keystrokes or 10 mouse moves) before you used /dev/urandom, then you are safe. The interaction can have reboots in between. This really only applise in a special sutuation where the system was not able to fill the entopy pool. An attack on the seed is only possible under similar circumstances, i.e. /dev/urandom before the keystrokes and/or mouse moves happened and basically was still in state the seed gave it. Do not worry with regular key generation! If you typed "cryptsetup" manually, that will already have made you pretty safe. This is for a special situation only. Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@xxxxxxxxxxx GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans If it's in the news, don't worry about it. The very definition of "news" is "something that hardly ever happens." -- Bruce Schneier _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
