Creating UUID and UDID in iOS 7

Question

I want to create UUID, I have code below which can create UUID, how can I create UDID with multiple vendors same ID in iOS7?

+ (NSString*) stringWithNewUUID
{
    CFUUIDRef uuidObj = CFUUIDCreate(nil);
    NSString *newUUID = (NSString*)CFUUIDCreateString(nil, uuidObj);
    CFRelease(uuidObj);
    return newUUID;
}

Answer 1

The CFUUIDCreate function produces a version 4 UUID which is taken entirely from a pseudo-random number generator. There are no timestamps or MAC addresses embedded in this type of UUID. (That refers to the little-used version 1 flavour.) These are safe to use for nearly all applications.

Answer 2

This method returns random UUID in iOS 6 and above

[[UIDevice currentDevice]identifierForVendor]