Re: /dev/random vs. /dev/urandom

Andries Brouwer
2005-01-07T23:33:20Z

On Fri, Jan 07, 2005 at 05:39:46PM -0500, linux-os wrote:

> Also, the following shows that the AND operation will destroy
> the randomness of the data. In this case I AND with 1, which
> should produce as many '1's as '0's, ... and clearly does not.

You do not sound like a reliable source of information
about randomness.

> LINUX> gcc -Wall -O2 -o xxx xxx.c
> LINUX> ./xxx
> Trying /dev/random
> 0100000101010000010001000101000000000000000101000100010000000101
> odds = 14 evens = 18
> Trying /dev/urandom
> 0001010001000100000101000100010001000000000000000000010000000000
> odds = 10 evens = 22
> LINUX> ./xxx
> Trying /dev/random
> 0100000100010101000101010101010101000100010000010001010000000101
> odds = 20 evens = 12
> Trying /dev/urandom
> 0100000100000101010001000101010001010001000000010101010100010000
> odds = 18 evens = 14