UDID or IMEI- which is better?

Question

When developing an app that requires me to uniquely identify phone users. I was hoping for some advice on whether it is best to use a phone's UDID or IMEI. Are there any advantages/disadvantages to using either. All comments would be greatly appreciated

Answer 1

Pros of ANDROID_ID:

1. Settings.Secure.ANDROID_ID. This is a 64-bit quantity that is generated and stored when the device first boots (ANDROID_ID is not unique for android 2.2 and from 4.2)

Cons of ANDROID_ID:

1. ANDROID_ID can change on factory reset.

2. ANDROID_ID can be null

3. It can be easily changed on a rooted phone

4. Several devices by several manufacturers are affected by the ANDROID_ID bug in 2.2 and all of them have the same ANDROID_ID, which is 9774d56d682e549c. Which is also the same device id reported by the emulator

   Docs: http://android-developers.blogspot.in/2011/03/identifying-app-installations.html

5. ANDROID_ID no longer uniquely identifies a device: https://stackoverflow.com/a/13465373/150016

Pros of IMEI

1. IMEI number is always unique.

Cons of IMEI

1. Many device don't have IMEI number i.e Samsung galaxy tab 2

Important Links

• android device id confusion
• http://android-developers.blogspot.in/2011/03/identifying-app-installations.html
• Is there a unique Android device ID?