PHP password generator

function generatePassword($length=9, $strength=0) {
$vowels = 'aeuy';
$consonants = 'bdghjmnpqrstvz';
if ($strength & 1) {
$consonants .= 'BDGHJLMNPQRSTVWXZ';
}
if ($strength & 2) {
$vowels .= "AEUY";
}
if ($strength & 4) {
$consonants .= '23456789';
}
if ($strength & {
$consonants .= '@#$%';
}

$password = '';
$alt = time() % 2;
srand(time());
for ($i = 0; $i < $length; $i++) {
if ($alt == 1) {
$password .= $consonants[(rand() % strlen($consonants))];
$alt = 0;
} else {
$password .= $vowels[(rand() % strlen($vowels))];
$alt = 1;
}
}
return $password;
}