How to generate unique identifier which should work in all iOS versions?

Question

I want to get the unique identifier which should support all iOS versions..Can any one help me on this issue. As you know that apple is deprecated the UDID method, So there is possibility to generate Unique id using wifi-mac address.But apple is going to remove the wifi mac address in iOS7 version.So my requirement is to generate a new unique code which should work in all iOS versions.Thanks in advance..

Note: Don't change the UDID once user restart the device or reinstall the application.

Answer 1

I was updating my application that was working based only on Unique Identifier which supported iOS 4.3 and above. So,

1) I was unable to use [UIDevice currentDevice].uniqueIdentifier; as it was no longer available

2) I could not use [UIDevice currentDevice].identifierForVendor.UUIDString because it was Available in iOS 6.0 and later only and was unable to use for lower iOS versions.

3) The mac address was not an option as it wasn't allowed in iOS-7

4) OpenUDID was deprecated some time ago and also had issues with iOS-6.

5) Advertisement identifiers were also not available for iOS-5 and below

Finally this was what i did

a) Added SFHFKeychainUtils to the project

b) Generated CFUUID key String

 CFUUIDRef cfuuid = CFUUIDCreate(kCFAllocatorDefault);
    udidString = (NSString*)CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, cfuuid));

c) Saved it to Key Chain Utils or else it will generate a new Unique Each Time

Final Code

+ (NSString *)GetDeviceID {
    NSString *udidString;
   udidString = [self objectForKey:@"deviceID"];
    if(!udidString)
    {
    CFUUIDRef cfuuid = CFUUIDCreate(kCFAllocatorDefault);
    udidString = (NSString*)CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, cfuuid));
    CFRelease(cfuuid);
        [self setObject:udidString forKey:@"deviceID"];
    }
    return udidString;
}

+(void) setObject:(NSString*) object forKey:(NSString*) key
{
    NSString *objectString = object;
    NSError *error = nil;
    [SFHFKeychainUtils storeUsername:key
                         andPassword:objectString
                      forServiceName:@"LIB"
                      updateExisting:YES
                               error:&error];

    if(error)
        NSLog(@"%@", [error localizedDescription]);
}

+(NSString*) objectForKey:(NSString*) key
{
    NSError *error = nil;
    NSString *object = [SFHFKeychainUtils getPasswordForUsername:key
                                                  andServiceName:@"LIB"
                                                           error:&error];
    if(error)
        NSLog(@"%@", [error localizedDescription]);

    return object;
}

For further Details

Answer 2

Now Device Identifier change to UUID.You can get UUID With the help of following code:

- (NSString *)getUUID
{
    NSString *UUID = [[NSUserDefaults standardUserDefaults] objectForKey:@"uniqueID"];
    if (!UUID) {
        CFUUIDRef theUUID = CFUUIDCreate(NULL);
        CFStringRef string = CFUUIDCreateString(NULL, theUUID);
        CFRelease(theUUID);
        UUID = [(__bridge NSString*)string stringByReplacingOccurrencesOfString:@"-"withString:@""];
        [[NSUserDefaults standardUserDefaults] setValue:UUID forKey:@"uniqueID"];
    }
    return UUID;
}

It's Work in all iOS version.

Answer 3

I don't have access to the code right now (can post in a few hours if you still need it) but what I've done is create a static method 'deviceIdentifier' in a helper class.

the method does a basic check for the current iOS version, returns UDID if below 6.0 and uniqueIdentifier otherwise

Let me know if you'd like the code for that and I'll post it when I can..it's only 10-15 lines or so if I remember right but makes a big difference as then you can just call '[myHelper deviceIdentifier]' wherever you need a device ID and not have to worry about which iOS version they are using