Re: /dev/random vs. /dev/urandom
From: Paulo Marques
Date: Fri Jan 07 2005 - 14:31:44 EST
Ron Peterson wrote:
When I compile and run the code below, the string of octal characters
generated by reading /dev/random contains long strings of zeroes. I was
under the impression that /dev/random is "more random" than
/dev/urandom, and will block when it runs out of entropy until it
gathers more. It's only when RAND_LEN is on the largish side that these
strings of zeroes appear.
[...]
read( fd, dat, RAND_LEN );
for( i = 0; i < RAND_LEN; i++ ) {
dat[i] = (dat[i] & 0x07) + '0';
This is wrong. You must check the return value of read to know how many
bytes have you actually gathered, instead of assuming RAND_LEN...
--
Paulo Marques - www.grupopie.com
"A journey of a thousand miles begins with a single step."
Lao-tzu, The Way of Lao-tzu
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