Symfony fos user password

fos_user.php

<?php 

$salt = base_convert(sha1(uniqid(mt_rand(), true)), 16, 36);

echo "Salt used: " . $salt ."<br/>";

echo "<br/>";

$password = 'new_password';
$salted = $password.'{'.$salt.'}';
$digest = hash('sha512', $salted, true);

for ($i=1; $i<5000; $i++) {
    $digest = hash('sha512', $digest.$salted, true);
}

$encodedPassword = base64_encode($digest);

echo "Password used: " . $password ."<br/>";

echo "<br/>";

echo "Encrypted Password: " . $encodedPassword ."<br/>";


?>