function _openid_dh_rand($stop)
{
static $duplicate_cache = array();
// Used as the key for the duplicate cache
$rbytes = _openid_dh_long_to_binary($stop);
if (array_key_exists($rbytes, $duplicate_cache)) {
list($duplicate, $nbytes) = $duplicate_cache[$rbytes];
} else {
if ($rbytes[0] == "") {
$nbytes = strlen($rbytes) - 1;
} else {
$nbytes = strlen($rbytes);
}
$mxrand = bcpow(256, $nbytes);
// If we get a number less than this, then it is in the
// duplicated range.
$duplicate = bcmod($mxrand, $stop);
if (count($duplicate_cache) > 10) {
$duplicate_cache = array();
}
$duplicate_cache[$rbytes] = array($duplicate, $nbytes);
}
do {
$bytes = "" . _openid_get_bytes($nbytes);
$n = _openid_dh_binary_to_long($bytes);
// Keep looping if this value is in the low duplicated range.
} while (bccomp($n, $duplicate) < 0);
return bcmod($n, $stop);
}
/**
* Is copy of _opend_dh_xorsecret() but uses PHP5 hash() function. Should be merged back into openid client
* for D7.
*
* @param long $shared
* @param string $secret
* @param string $algo
* @return binary string
*/
function _openid_provider_dh_xorsecret($shared, $secret, $algo = 'sha1')
{
$dh_shared_str = _openid_dh_long_to_binary($shared);
$sha1_dh_shared = hash($algo, $dh_shared_str, true);
$xsecret = "";
for ($i = 0; $i < strlen($secret); $i++) {
$xsecret .= chr(ord($secret[$i]) ^ ord($sha1_dh_shared[$i]));
}
return $xsecret;
}
