Re: Why does reading from /dev/urandom deplete entropy so much?


On Wed, 2007-12-05 at 09:49 -0500, Theodore Tso wrote:
On Wed, Dec 05, 2007 at 08:26:19AM -0600, Mike McGrath wrote:

Ok, whats going on here is an issue with how the smolt RPM installs the
UUID and how Fedora's Live CD does an install. It's a complete false alarm
on the kernel side, sorry for the confusion.

BTW, You may be better off using "uuidgen -t" to generate the UUID in
the smolt RPM, since that will use 12 bits of randomness from
/dev/random, plus the MAC, address and timestamp. So even if there is
zero randomness in /dev/random, and the time is January 1, 1970, at
least the MAC will contribute some uniqueness to the UUID.

I haven't checked how uuidgen uses the MAC, but I would suggest that
that is not something Fedora should jump at doing - although it would
help ensure unique UUIDs, it also contributes to the tinfoil hat
responses that usually come up with things like smolt.

Jon.



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