udid - Secure Android ID length?

Question

I am using the below code to get the android ID

 String android_id = Secure.getString(context.getContentResolver(),
            Secure.ANDROID_ID);

I am able to get the android ID but it's length is not fixed. In some phones I get a 16 length ID and in other I get 15 length ID.

I read in the documentation it is a 64 Hex decimal number so it should always return 16 digit string.

So is there something wrong I am doing?

Answer 1

The following code snippet from AOSP shows how the ANDROID_ID is generated:

String androidId = Long.toHexString(new SecureRandom().nextLong());

The method Long.toHexString is known to suppress leading zeros. Therefore prepending the ANDROID_ID with zeros in case it's length is less than 16 should be to correct way to get a full 16 digits ANDROID_ID.