From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: [PATCH 1/1] random.4: mention PRNG used by urandom Date: Sat, 10 Jan 2015 14:34:18 +0100 Message-ID: <54B12A5A.1050808@gmail.com> References: <1417042709-16767-1-git-send-email-xypron.glpk@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1417042709-16767-1-git-send-email-xypron.glpk-Mmb7MZpHnFY@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Heinrich Schuchardt Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Theodore Ts'o List-Id: linux-man@vger.kernel.org On 11/26/2014 11:58 PM, Heinrich Schuchardt wrote: > /dev/urandom uses a pseudo random number generator to replace > missing entropy. Thanks, Heinrich. Applied. Cheers, Michael > Signed-off-by: Heinrich Schuchardt > --- > man4/random.4 | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/man4/random.4 b/man4/random.4 > index 44d9e34..1be19b8 100644 > --- a/man4/random.4 > +++ b/man4/random.4 > @@ -63,8 +63,9 @@ will be set to > .LP > A read from the \fI/dev/urandom\fP device will not block > waiting for more entropy. > -As a result, if there is not sufficient entropy in the > -entropy pool, the returned values are theoretically vulnerable to a > +If there is not sufficient entropy, a pseudorandom number generator is used > +to create the requested bytes. > +As a result, in this case the returned values are theoretically vulnerable to a > cryptographic attack on the algorithms used by the driver. > Knowledge of how to do this is not available in the current unclassified > literature, but it is theoretically possible that such an attack may > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html