Let’s work through some code to do an encrypted backup. This feature is available to you if you are using SQL Server 2014 onwards but I decided to use SQL Server 2017.
To encrypt during backup, you must specify an encryption algorithm, and an “encryptor” to secure the encryption key. I have decided to use the following options:
A really quick one today, something that made me think for a minute and I thought it might make others think too. So you have enabled TDE – Transparent Data Encryption (you can see these previous posts here: https://blobeater.blog/?s=tde&submit=Search) on your SQL Server database and in the back of your mind you know TempDB gets encrypted too.
TDE (Transparent Data Encryption) encrypts the data files at rest but don’t forget that it also encrypts your backup file too. I fancied looking inside a backup of my database before enabling TDE and comparing it to when enabled.
Working with a couple of databases that needed TDE I noticed when I enabled one of them that it was stuck on “encryption in progress” for quite a while.
All About Data 