Messages in this thread | | | From | Andreas Dilger <> | Date | Sat, 17 Aug 2002 00:05:07 -0600 | Subject | Re: Problem with random.c and PPC |
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On Aug 16, 2002 19:45 -0500, Oliver Xymoron wrote: > Realistically, the hashing done by /dev/urandom is probably strong > enough for most purposes. It's as cryptographically strong as whatever > block cipher you're likely to use with it. /dev/random goes one step > further and tries to offer something that's theoretically > unbreakable. Useful for generating things like large public keys, less > useful for generating the session keys used by SSL and the > like. They're easier to break by direct attack.
One of the problems, I believe, is that reading from /dev/urandom will also deplete the entropy pool, just like reading from /dev/random. The only difference is that when the entropy is gone /dev/random will stop and /dev/urandom will continue to provide data.
If you are in there fixing things, it might make sense to have /dev/urandom extract entropy from the random pool far less often than /dev/random. This way people who use /dev/urandom for a source of less-strong randomness (e.g. TCP sequence numbers or whatever), will not be shooting themselves in the foot for when they need a 2048-byte PGP key, if they are low on entropy sources.
Cheers, Andreas -- Andreas Dilger http://www-mddsp.enel.ucalgary.ca/People/adilger/ http://sourceforge.net/projects/ext2resize/
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