Messages in this thread | | | From | Jon Masters <> | Subject | Re: Why does reading from /dev/urandom deplete entropy so much? | Date | Sun, 09 Dec 2007 01:52:05 -0500 |
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On Sun, 2007-12-09 at 06:21 +0100, Willy Tarreau wrote:
> Wouldn't it be possible to mix the data with the pid+uid of the reading > process so that even if another one tries to collect data from urandom, > he cannot predict what another process will get ? BTW, I think that the > tuple (pid,uid,timestamp of open) is unpredictable and uncontrollable > enough to provide one or even a few bits of entropy by itself.
Timestamp perhaps, but pid/uid are trivially guessable in automated environments, such as LiveCDs. And if you're also running on an embedded system without a RTC (common, folks like to save a few cents) then it's all pretty much "trivially" guessable on some level.
Jon.
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