How to encrypt the full database?

When you want to help prevent unauthorized use of an Access database, consider encrypting the database by setting a password. If you know the password for an encrypted database, you can also decrypt the database and remove its password.
 
TDE transparently encrypts data at rest in Oracle Databases. It stops unauthorized attempts from the operating system to access database data stored in files, without impacting how applications access the data using SQL. TDE can encrypt entire application tablespaces or specific sensitive columns. TDE is fully integrated with Oracle database. Encrypted data remains encrypted in the database, whether it is in tablespace storage files, temporary tablespaces, undo tablespaces, or other files that Oracle Database relies on such as redo logs. Also, TDE can encrypt entire database backups (RMAN) and Data Pump exports