function read_mcrypt()
{
return base64_encode(mcrypt_create_iv(12, MCRYPT_DEV_URANDOM));
}
function read_urandom()
{
if ($fh = @fopen('/dev/urandom', 'rb')) {
$output = fread($fh, 12);
fclose($fh);
}
return base64_encode($output);
}
$imax = 10000;
$t0 = microtime(true);
for ($i = $imax; $i >= 0; --$i) {
$a = read_urandom();
}
$t1 = microtime(true);
printf("file /dev/urandom: %f\n", $t1 - $t0);
$t0 = microtime(true);
for ($i = $imax; $i >= 0; --$i) {
$a = read_mcrypt();
}
$t1 = microtime(true);
printf("mcrypt: %f\n", $t1 - $t0);
$t0 = microtime(true);
for ($i = $imax; $i >= 0; --$i) {
$a = gen_rand_str_24();
}
$t1 = microtime(true);
printf("rand: %f\n", $t1 - $t0);
function generate_secret_key($len)
{
if (($key = read_urandom($len)) == NULL) {
// poor man's choice
$key = poor_rand_string($len);
}
return base64_encode($key);
}