AppUniqueIdentifier.h

//
//  AppUniqueIdentifier.h
//  ReinstallationUdid
//
//  Created by William LaFrance on 2/27/13.
//  Copyright (c) 2013 William LaFrance. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface AppUniqueIdentifier : NSObject

+ (NSString *)uniqueIdentifier;

@end

AppUniqueIdentifier.m

//
//  AppUniqueIdentifier.m
//  ReinstallationUdid
//
//  Created by William LaFrance on 2/27/13.
//  Copyright (c) 2013 William LaFrance. All rights reserved.
//

#import "AppUniqueIdentifier.h"

@implementation AppUniqueIdentifier

+ (NSString *)uniqueIdentifier
{
    CFUUIDRef uuid;
    NSUserDefaults *defaults = NSUserDefaults.standardUserDefaults;
    if (![defaults valueForKey:@"UUID"]) {
        uuid = CFUUIDCreate(NULL);
        NSString *uuidString = (__bridge NSString *)CFUUIDCreateString(NULL, uuid);
        CFRelease(uuid);
        [defaults setObject:uuidString forKey:@"UUID"];
        [defaults synchronize];
        return uuidString;
    } else {
        NSString *uuidString = [defaults objectForKey:@"UUID"];
        return uuidString;
    }
}

@end