Backups of NSS volumes are not encrypted, unless it is a feature of the backup software or hardware you use. Although data is stored on an encrypted NSS volume, its data is transmitted and backed up in an unencrypted format.
Use backup methods that protect data transmitted between the server and the backup media, according to your security needs.
Use one of the following methods to encrypt the data for backup:
Use backup software that is able to encrypt data when you back it up. This method has performance and manageability challenges, especially for managing encryption keys.
Use an encryption appliance that encrypts sensitive backup media as data is backed up.
If you transport and store media offsite, use a company that specializes in media shipment and storage. This way, your tapes are tracked via barcodes, stored in environmentally friendly conditions, and are handled by a company whose reputation rests on its ability to handle your media properly.