ios - Differences between UDID and UUID

Question

(This question already has answers here): question from:https://stackoverflow.com/questions/21872233/differences-between-udid-and-uuid

Answer 1

UUID (Universally Unique IDentifier) Is on a per-app basis. identifies an app on a device. As long as the user doesn’t completely delete the app, then this identifier will persist between app launches, and at least let you identify the same user using a particular app on a device. Unfortunately, if the user completely deletes and then reinstalls the app then the ID will change.

UDID (Unique Device Identifier) A sequence of 40 hexadecimal characters that uniquely identify an ios device. This value can be retrieved through iTunes, or found using UIDevice -uniqueIdentifier. Derived from hardware details like MAC address.