For greater security you can encrypt data that you export to Object Storage. When data on Object Storage is encrypted you can decrypt the data you import or when you use the data in an external table.

• Encrypt Data While Exporting to Object Storage
  You can encrypt table data while exporting to Object Storage.
• Decrypt Data While Importing from Object Storage
  You can decrypt and load data from encrypted files stored in Object Storage. You can also decrypt encrypted data on Object Storage that you use in an external table.