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

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

[Heinrich Schuchardt]

/dev/urandom uses a pseudo random number generator to replace
missing entropy.

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
-- 
2.1.3

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

[Michael Kerrisk (man-pages)]

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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