?=-` '; $chars = str_split($chars); $ch = array(); // fill up $ch until we reach $length while (count($ch) < $length) { $n = $length - count($ch); $keys = array_rand($chars, $n > count($chars) ? count($chars) : $n); if ($n == 1) { $ch[] = $chars[$keys]; break; } shuffle($keys); foreach ($keys as $key) $ch[] = $chars[$key]; } $chars = $ch; return implode('', $chars); } public static function make_confusing($string) { $chars = str_split($string); foreach ($chars as &$c) { if (rand(0, 2) != 0) $c = utf8tohtml($c); else $c = mb_encode_numericentity($c, array(0, 0xffff, 0, 0xffff), 'UTF-8'); } return implode('', $chars); } public function __construct(array $salt = array()) { global $config; if (!empty($salt)) { // create a salted hash of the "extra salt" $this->salt = implode(':', $salt); } else { $this->salt = ''; } shuffle($config['spam']['hidden_input_names']); $input_count = rand($config['spam']['hidden_inputs_min'], $config['spam']['hidden_inputs_max']); $hidden_input_names_x = 0; for ($x = 0; $x < $input_count ; $x++) { if ($hidden_input_names_x === false || rand(0, 2) == 0) { // Use an obscure name $name = $this->randomString(rand(10, 40)); } else { // Use a pre-defined confusing name $name = $config['spam']['hidden_input_names'][$hidden_input_names_x++]; if ($hidden_input_names_x >= count($config['spam']['hidden_input_names'])) $hidden_input_names_x = false; } if (rand(0, 2) == 0) { // Value must be null $this->inputs[$name] = ''; } elseif (rand(0, 4) == 0) { // Numeric value $this->inputs[$name] = (string)rand(0, 100); } else { // Obscure value $this->inputs[$name] = $this->randomString(rand(5, 100), true, true); } } } public function html($count = false) { global $config; $elements = array( '', '', '', '', '', '', '', '', '' ); $html = ''; if ($count === false) { $count = rand(1, count($this->inputs) / 15); } if ($count === true) { // all elements $inputs = array_slice($this->inputs, $this->index); } else { $inputs = array_slice($this->inputs, $this->index, $count); } $this->index += count($inputs); foreach ($inputs as $name => $value) { $element = false; while (!$element) { $element = $elements[array_rand($elements)]; if (strpos($element, 'textarea') !== false && $value == '') { // There have been some issues with mobile web browsers and empty

's.
					$element = false;
				}
			}
			
			$element = str_replace('%name%', utf8tohtml($name), $element);
			
			if (rand(0, 2) == 0)
				$value = $this->make_confusing($value);
			else
				$value = utf8tohtml($value);
			
			if (strpos($element, 'textarea') === false)
				$value = str_replace('"', '"', $value);
			
			$element = str_replace('%value%', $value, $element);
			
			$html .= $element;
		}
		
		return $html;
	}
	
	public function reset() {
		$this->index = 0;
	}
	
	public function hash() {
		global $config;
		
		// This is the tricky part: create a hash to validate it after
		// First, sort the keys in alphabetical order (A-Z)
		$inputs = $this->inputs;
		ksort($inputs);
		
		$hash = '';
		// Iterate through each input
		foreach ($inputs as $name => $value) {
			$hash .= $name . '=' . $value;
		}
		// Add a salt to the hash
		$hash .= $config['cookies']['salt'];
		
		// Use SHA1 for the hash
		return sha1($hash . $this->salt);
	}
}

function _create_antibot($board, $thread) {
	global $config;
	
	$antibot = new AntiBot(array($board, $thread));
	
	query('DELETE FROM ``antispam`` WHERE `expires` < UNIX_TIMESTAMP()') or error(db_error());
	
	if ($thread)
		$query = prepare('UPDATE ``antispam`` SET `expires` = UNIX_TIMESTAMP() + :expires WHERE `board` = :board AND `thread` = :thread AND `expires` IS NULL');
	else
		$query = prepare('UPDATE ``antispam`` SET `expires` = UNIX_TIMESTAMP() + :expires WHERE `board` = :board AND `thread` IS NULL AND `expires` IS NULL');
	
	$query->bindValue(':board', $board);
	if ($thread)
		$query->bindValue(':thread', $thread);
	$query->bindValue(':expires', $config['spam']['hidden_inputs_expire']);
	$query->execute() or error(db_error($query));
	
	$query = prepare('INSERT INTO ``antispam`` VALUES (:board, :thread, :hash, UNIX_TIMESTAMP(), NULL, 0)');
	$query->bindValue(':board', $board);
	$query->bindValue(':thread', $thread);
	$query->bindValue(':hash', $antibot->hash());
	$query->execute() or error(db_error($query));
	
	return $antibot;
}

function checkSpam(array $extra_salt = array()) {
	global $config, $pdo;

if (!isset($_POST['hash']))
		return true;

$hash = $_POST['hash'];

if (!empty($extra_salt)) {
		// create a salted hash of the "extra salt"
		$extra_salt = implode(':', $extra_salt);
	} else { 
		$extra_salt = '';
	}

// Reconsturct the $inputs array
	$inputs = array();

foreach ($_POST as $name => $value) {
		if (in_array($name, $config['spam']['valid_inputs']))
			continue;

$inputs[$name] = $value;
	}

// Sort the inputs in alphabetical order (A-Z)
	ksort($inputs);

$_hash = '';

// Iterate through each input
	foreach ($inputs as $name => $value) {
		$_hash .= $name . '=' . $value;
	}

// Add a salt to the hash
	$_hash .= $config['cookies']['salt'];

// Use SHA1 for the hash
	$_hash = sha1($_hash . $extra_salt);

if ($hash != $_hash)
		return true;

$query = prepare('SELECT `passed` FROM ``antispam`` WHERE `hash` = :hash');
	$query->bindValue(':hash', $hash);
	$query->execute() or error(db_error($query));
	if ((($passed = $query->fetchColumn(0)) === false) || ($passed > $config['spam']['hidden_inputs_max_pass'])) {
		// there was no database entry for this hash. most likely expired.
		return true;
	}

return $hash;
}

function incrementSpamHash($hash) {
	$query = prepare('UPDATE ``antispam`` SET `passed` = `passed` + 1 WHERE `hash` = :hash');
	$query->bindValue(':hash', $hash);
	$query->execute() or error(db_error($query));
}