Apple-safe UUID Generation

gistfile1.m

// requires UICKeyChainStore lib

NSString *uniqueIdentifier;

#if TARGET_IPHONE_SIMULATOR
    uniqueIdentifier = @"SIMULATOR";
#else
    uniqueIdentifier = [UICKeyChainStore stringForKey:@"UUID" service:@"joshavant"];

    if(![uniqueIdentifier length] > 0)
    {
        // generate a new unique ID
        CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);
        CFStringRef stringRef = CFUUIDCreateString (kCFAllocatorDefault,uuidRef);
        NSString* newUUID = (__bridge NSString *)stringRef;
        [UICKeyChainStore setString:newUUID forKey:@"UUID" service:@"joshavant"];
        uniqueIdentifier = newUUID;
        CFRelease(stringRef);
        CFRelease(uuidRef);
    }
#endif

// now uniqueIdentifier is your effective UUID