Re: Entropy Pool Contents

Phillip Susi
2006-11-27T16:15:48Z

Gunter Ohrner wrote:
> IMHO something really fishy's going on there. If I explicitely write data
> into the pool, it shouldd not stay at "zero", from wwhat I understood about
> how /dev/*random work.
>

<snip>

> I'm mainly wondering why writing stuff to /dev/*random does not change the
> entropy from zero to at least any low non-zero value...
>

I ran into this the other day myself and when I investigated the kernel
code, I found that writes to /dev/random do accept the data into the
entropy pool, but do NOT update the entropy estimate. In order to do
that, you have to use a root only ioctl to add the data and update the
estimate. I am not sure why this is, or if there is a tool already
written somewhere to use this ioctl, maybe someone else can comment?