Oracle TDE - what mean rotate (rekey) encryption key? why and when?

Question

Maybe I missed something. Reading about Oracle transparent data encryption (TDE), some references say about rekey (or rotate) the master key. But why should we do that?

I mean, why to execute the following command?

ADMINISTER KEY MANAGEMENT SET KEY IDENTIFIED BY teste123;

I am sure this don't mean change wallet (keystore) password, since for that we need to execute:

ADMINISTER KEY MANAGEMENT ALTER KEYSTORE PASSWORD FORCE KEYSTORE IDENTIFIED BY "teste123" SET "123teste" WITH BACKUP USING 'OLDKEY';

Answer 1

ADMINISTER KEY MANAGEMENT SET KEY IDENTIFIED BY teste123;

This command does change the master encryption key. You do this for the same reason that you would change a password: to reduce the likelihood of it being stolen, compromised, or somehow used against you. It's just good security.