看板FB_security
标 题Re: Collecting entropy from device_attach() times.
发信站NCTU CS FreeBSD Server (Thu Sep 20 19:20:56 2012)
转信站ptt!csnews.cs.nctu!news.cs.nctu!.cs.nctucs.nctu!.org!ownorg!owner-free
RW <
[email protected]> writes:
> You're basing a model for all devices on a single sound card, that
> doesn't seem safe to me. Isn't it possible that a device could take a
> long and well defined time?
Please understand that the timers used here have a resolution of around
1e-8 to 1e-10 seconds. You may be able to predict the first six digits
with reasonable accuracy - in fact, the first four or five will almost
always be 0, except for devices with moving parts - but anything beyond
that is a crapshoot, even in a virtual machine.
(I am speaking, of course, of decimal digits - multiply by 3.322 for the
corresponding number of bits)
DES
--=20
Dag-Erling Sm=C3=B8rgrav -
[email protected]
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