Re: [PATCH 1/1] random.4: mention PRNG used by urandom

["Michael Kerrisk (man-pages)" <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.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 <xypron.glpk-Mmb7MZpHnFY@public.gmane.org>
> ---
>  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/
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