Re: /dev/random: really secure?

From: Kurt Garloff (
Date: Tue Dec 19 2000 - 06:49:48 EST

On Mon, Dec 18, 2000 at 04:33:13PM -0500, Theodore Y. Ts'o wrote:
> Note that writing to /dev/random does *not* update the entropy estimate,
> for this very reason. The assumption is that inputs to the entropy
> estimator have to be trusted, and since /dev/random is typically
> world-writeable, it is not so trusted.

It should not be world-writeable, IMHO. So the only one who can feed entropy
there is root, who should know aht (s)he's doing ...
Here (SuSE Linux 7.x), it is 644:
crw-r--r-- 1 root root 1, 8 Dec 17 22:41 /dev/random
crw-r--r-- 1 root root 1, 9 Dec 17 22:41 /dev/urandom


Kurt Garloff  <>                          Eindhoven, NL
GPG key: See mail header, key servers         Linux kernel development
SuSE GmbH, Nuernberg, FRG                               SCSI, Security

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