This encryption process works so that users who take data by way of database backup. This encryption works when the user restore the database on another server it will fail because it does not have a wallet that has been created. For more details follow these steps :
Set Master Key
alter system set "_db_discard_lost_masterkey" = true;
Create Key Management
administer key management create keystore '/u01/app/oracle/product/12.1.0/db_1/owm/wallets/oracle' identified by "passw0rd";
