PHP-decrypt:

function decrypt($msgb64,$password)
{
    $airqpass = $password;
	if (strlen($airqpass) < 32) {
		for ($i = strlen($airqpass); $i < 32; $i++) {
			$airqpass = $airqpass . '0';
		}
	} else {
		if (strlen($airqpass) > 32) {
			$airqpass = substr($airqpass,0,32);
		}
	}

	$key = utf8_encode ($airqpass);
//	$cyphertext = base64_decode ($msgb64);
//	But with verly long messages there could be some problems in base64_decode
	$decoded = "";
	for ($i=0; $i < ceil(strlen($msgb64)/256); $i++)
	   $decoded = $decoded . base64_decode(substr($msgb64,$i*256,256));
	$cyphertext = $decoded;

	$iv = substr($cyphertext,0,16);
	$cyphertext = substr($cyphertext,16,strlen($cyphertext));

	$decrypted = openssl_decrypt($cyphertext, 'aes-256-cbc', $key, OPENSSL_RAW_DATA, $iv);
	
	return utf8_encode($decrypted);
}

PHP-encrypt:

function encrypt($msgb64,$password)
{
    $airqpass = $password;
	if (strlen($airqpass) < 32) {
		for ($i = strlen($airqpass); $i < 32; $i++) {
			$airqpass = $airqpass . '0';
		}
	} else {
		if (strlen($airqpass) > 32) {
			$airqpass = substr($airqpass,0,32);
		}
	}

	$key = utf8_encode ($airqpass);
	
	$iv = substr(openssl_random_pseudo_bytes(32),0,16);

	$encrypted = openssl_encrypt($msgb64, 'aes-256-cbc', $key, OPENSSL_RAW_DATA, $iv);
	return base64_encode($iv . $encrypted);
}