KlugDeviceId

<extensions>
    <extensionID>com.klug.deviceid</extensionID>
</extensions>

import com.klug.deviceid.DeviceId;
import flash.events.Event;
import flash.net.*;

// read once at start and keep it: ANDROID_ID on Android, identifierForVendor on iOS
var deviceId:String = DeviceId.getInstance().uniqueId;

function login( user:String, password:String ):void
{
    var vars:URLVariables = new URLVariables();
    vars.user     = user;
    vars.password = password;
    vars.device   = deviceId;     // your server binds the licence or the push token to it

    var req:URLRequest = new URLRequest( "https://your.server/login" );
    req.method = URLRequestMethod.POST;
    req.data   = vars;

    var loader:URLLoader = new URLLoader();
    loader.addEventListener( Event.COMPLETE, onLoginResult );
    loader.load( req );
}

var dev:DeviceId = DeviceId.getInstance();

// Android: ANDROID_ID stays the same after uninstall and reinstall; only a
// factory reset changes it. From Android 8 it is specific to your signing key.
var anchor:String = dev.androidId;

if ( anchor != "" )
    checkTrial( anchor );     // your server: has this device used the trial before?
else
    checkTrialOnIOS();        // iOS: androidId is always "" and identifierForVendor is
                              // reset on uninstall, use KlugKeychain as the anchor there

import flash.utils.setTimeout;

function readDeviceId():void
{
    var dev:DeviceId = DeviceId.getInstance();
    if ( !dev.isSupported )
    {
        useOwnDesktopId();        // desktop: isSupported is false, every getter returns ""
        return;
    }

    var id:String = dev.uniqueId;
    if ( id == "" )
        setTimeout( readDeviceId, 1000 );   // iOS can briefly have no value: ask again
    else
        onDeviceId( id );
}