Matching an NSString with part of a text paragraph on a website. - iPhone SDK

Question

Hello, So basically I'm working on an application, and one of the features is an anti-cracking feature. It checks the webpage for the UDID number of the device, and if it is there, it allows the application to run, if it's not there, it runs exit(0);. So far, this is what I have.

This is in my AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 
    [window addSubview:mainViewController.view];

    if ([[[UIDevice currentDevice] uniqueIdentifier] isEqualToString:[NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://example.com" ]]]) {
        NSLog(@"Match!");
        [window makeKeyAndVisible];
    }
    else {
        NSLog(@"No match.");
        alertView = [[UIAlertView alloc] initWithTitle:@"Access denied!" message:@"You aren't using an official version of this application." delegate:self cancelButtonTitle:@"Okay" otherButtonTitles:nil];
        [alertView show];
        [alertView release];
    }

    return YES;
}

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex {
    if (buttonIndex == 0) {
    exit(0);
    }
}

And so basically, where you see

if ([[[UIDevice currentDevice] uniqueIdentifier] isEqualToString:[NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://example.com" ]]]) {

When it runs that, it can only detect all of the text, rather than indexing it and finding that UDID number. So I can only put 1 UDID number on there, therefore making every user's application crash. I want to set it up so that I can have as many things on there as I want, and it will just index it and search for that UDID number on the page. Can anybody help me please? It's very important!

Thank you very much!

Answer 1

Yay so if I buy your app and your server is down (stringWithContentsOfURL returns nil) your app wil think I pirated your software!

How about spending time on bug free end-user features instead of this?

Answer 2

As for me, it would be easier to generate an xml of UDIDs, then parse it into an array and then compare each element with paticular UDID

Answer 3

I don't understand how this is supposed to be an "anti-cracking feature", unless you plan to somehow obtain the UDIDs of all the devices of a user who has legally purchased your app through iTunes. You can't get such a list. And even if you could, it might be a violation of Apple's developer agreement, especially the section on privacy and storage of information.

So in summary:

• This solution is fundamentally and fatally flawed.
• There are other anti-cracking techniques that will be more effective, especially those that use a softer approach... but none will be perfect.
• As St3fan says, your technique requires a working Internet connection, which is not something you can always assume. In which case, this technique does not fail gracefully. In which case, Apple can reject your app. It will not be "[Apple's] problem" if it fails. It is your problem.

And finally, a 0% accept rate on 10 questions doesn't bode well for getting advice in the future here. You should know that sticks out like a sore thumb.

Answer 4

Hi.

This is useful for enterprise ad hoc applications. Did you find a solution for this Daniel?

Cheers, Ompah