LOGING
<?php
$db = new SQLite3('my_database') or die('unable to open database');
$user = $_POST['username'];
$pass = $_POST['password'];



$result = $db->querySingle("SELECT * FROM users WHERE username = '$user'", true) or die('Query failed');

$salt = $result['salt'];

$options = [
    'cost' => 11,
    'salt' => $salt,
];


$pass = password_hash($pass, PASSWORD_BCRYPT, $options);

if($pass == $result['password']){
    echo "Welcome";
}
        else{
    echo "Invalid username or password";
}


?>





create user
<?php
$db = new SQLite3('my_database') or die('unable to open database');
$query = <<<EOD
    CREATE TABLE IF NOT EXISTS users (
    username STRING PRIMARY KEY,
    password STRING,
    salt STRING)
EOD;
$db->exec($query) or die('Create db failed');
$user = $_POST['username'];
$pass = $_POST['password'];
$salt =  mcrypt_create_iv(22, MCRYPT_DEV_URANDOM);


$options = [
    'cost' => 11,
    'salt' => $salt,
];

$pass = password_hash($pass, PASSWORD_BCRYPT, $options);

$query = <<<EOD
INSERT INTO users VALUES ( '$user', '$pass', '$salt' )
EOD;

$db->exec($query) or die("Unable to add user $user");

 echo "Account created";


?>