Re: /dev/random -- can I enlarge the `randomness stock'?

From: Jeff Garzik (jgarzik@mandrakesoft.com)
Date: Sun May 21 2000 - 02:07:10 EST


getrpml@moscito.org wrote:
> For an application, I need a random seed with about 25000 bits
> of randomness from time to time. Unfortunately, /dev/random in
> the standard kernel only stocks 512 bytes of randomness. Can I
> enlarge it with no ill effect merely by changing one variable
> in the kernel's random.c? [Here core memory is no problem.] I
> have read the source but am loathe to try anything on a running
> machine with a duty. Thanks.

> Also, can some kind soul inform me how quickly is the stock of
> randomness replenished in a `typical' machine, assuming there
> to be such a beast? The machine running my program will likely
> have 512MB of ram, 9Gx3 RAID-5 SCSI drives, and dual PIII's.

Randomness is replenished through irregular events like SCSI/kbd/mouse
interrupts.

But if you need a lot of randomness, you should get hardware built
specifically for that. I wrote a driver for the i810 built-in random
number generator, but you probably want something a lot better (and not
built into the motherboard) for a large quantity of random values.

i810 driver at http://gtf.org/garzik/drivers/

        Jeff

-- 
Jeff Garzik              | Liberty is always dangerous, but
Building 1024            | it is the safest thing we have.
MandrakeSoft, Inc.       |      -- Harry Emerson Fosdick

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