Secure password generator

Generates a random 8 digit password using letters as well as numbers.

I use this for generating VERY random passwords for my system management utility. If people use passwords such as "Zj4Hf83A" or "A94J3ha1" then your system will be much more secure than passwords such as "sex" or "mydaughtersname". You can change $possiblechars to contain whatever you want it to (such as the -, or _, etc.)

function GenPassword() {
$possiblechars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrsturv wxyz1234567890";
srand((double)microtime()*1000000);
$rnd1 = rand(0, count($possiblechars));
$letter1 = $possiblechars[$rnd1];
srand((double)microtime()*1000000);
$rnd2 = rand(0, count($possiblechars));
$letter2 = $possiblechars[$rnd2];
srand((double)microtime()*1000000);
$rnd3 = rand(0, count($possiblechars));
$letter3 = $possiblechars[$rnd3];
srand((double)microtime()*1000000);
$rnd4 = rand(0, count($possiblechars));
$letter4 = $possiblechars[$rnd4];
srand((double)microtime()*1000000);
$rnd5 = rand(0, count($possiblechars));
$letter5 = $possiblechars[$rnd5];
srand((double)microtime()*1000000);
$rnd6 = rand(0, count($possiblechars));
$letter6 = $possiblechars[$rnd6];
srand((double)microtime()*1000000);
$rnd7 = rand(0, count($possiblechars));
$letter7 = $possiblechars[$rnd7];
srand((double)microtime()*1000000);
$rnd8 = rand(0, count($possiblechars));
$letter8 = $possiblechars[$rnd8];

$newpwd = "$letter1$letter2$letter3$letter4$letter5$letter6$ letter7$letter8";

return $newpwd;
}