The backup and restore process of any protected database can be performed in usual way without any decryption. Any backup produced is always automatically encrypted using the AES-128 algorithm. These backups are not system dependent and so can freely be copied to another server/computer. Restoring data to the same encrypted database is exceptionally straight forward, however if you plan to restore the data to another database you will need to prepare the database beforehand as it is not possible to restore encrypted data to an unencrypted database. In addition to this you cannot restore backup data to another encrypted database unless the passwords are the same.

All kinds of restore to the same database are performed like any normal restore procedure! Things to do if you want to do FULL RESTORE to another database (unprotected or to database encrypted with another key files - password does not matter):

Locate the existing database files. These are usually in the Data folder of the SQL Server instance.
Copy the DBDefence keys from the source database to that location. This will require 1 key file for each database file. For example, if you have an encrypted database which consists of 2 files: customers.mdf and customers_log.ldf, then you will also require the 2 key files :customers_log.dbd_key and customers.dbd_key.
If you plan to restore it to another database called customers2 which itself consist of 2 files :customers2.mdf and customers2_log.ldf, then you will need to copy one of the existing key files (they are the same) to create to 2 new files called customers2.dbd_key and customers2_log.dbd_key
Restart server instance.
At this stage database will be unavailable or even marked as suspicious, do not panic as this is normal at that stage.
Everything should now be ready, perform the restore as you would do normally.

Backup compression

Encrypted backup as any other encrypted data can hardly be compressed. SQL Server 2008 offers an opportunity to compress data before encryption. We recommend to use that option if you need to use compression.