easiest way to uniquely identify a user of an iphone app

Question

What's the easiest way to uniquely identify a user of an iphone app? I've seen some app only asks for phone number to 'register', isn't that unsafe or is there something I missed?

Got a Q about uniqueIdentifier, does it reset after some sort of reset/format or change of SIM card?

Would a traditional username/email/password be the safer approach?

Thanks.

Answer 1

Apple phasing out UDID

http://www.appleinsider.com/articles/11/08/19/inside_ios_5_privacy_change_kills_app_developers_access_to_udid.html

Answer 2

The easiest way would probably be by device ID :

 UIDevice *myDevice = [UIDevice currentDevice];
 NSString *uniqueIdentifier = [myDevice uniqueIdentifier];

This will uniquely identify the device, not the user.

If you want to identify the user, I would suggest using iTunes/Apple accounts, since users will already have that, and you don't have to mess with phone numbers which aren't applicable to iPods.

Answer 3

Maybe email address and password?

If you use Push Notification the user's device will have a unique token to all communication with your App. Maybe you could pull that token, then just not actually send the notification. Although the user has the option to deny the request, so you'd need a backup.

Answer 4

Unique identifier for an iPhone app

for safari: cookie the user - it works like a normal browser.