Back Up the Service Master Key
This article describes how to back up the Service Master key in SQL Server 2019 (15.x) by using Transact-SQL. The service master key is the root of the encryption hierarchy. It should be backed up and stored in a secure, off-site location. Creating this backup should be one of the first administrative actions performed on the server.
Before You Begin
Limitations and Restrictions
The master key must be open and, therefore, decrypted before it is backed up. If it is encrypted with the service master key, the master key does not have to be explicitly opened; however, if the master key is encrypted only with a password, it must be explicitly opened.
We recommend that you back up the master key as soon as it is created, and store the backup in a secure, off-site location.
Requires CONTROL permission on the database.
To back up the Service Master key
In SQL Server Management Studio, connect to the SQL Server instance containing the service master key you wish to back up.
Choose a password that will be used to encrypt the service master key on the backup medium. This password is subject to complexity checks. For more information, see Password Policy.
Obtain a removable backup medium for storing a copy of the backed-up key.
Identify an NTFS directory in which to create the backup of the key. This directory is where you will create the file specified in the next step. The directory should be protected with highly restrictive access control lists (ACLs).
In Object Explorer, connect to an instance of Database Engine.
On the Standard bar, click New Query.
Copy and paste the following example into the query window and click Execute.
-- Creates a backup of the service master key. USE master; GO BACKUP SERVICE MASTER KEY TO FILE = 'c:\temp_backups\keys\service_master_ key' ENCRYPTION BY PASSWORD = '3dH85Hhk003GHk2597gheij4'; GO
The file path to the key and the key's password (if it exists) will be different than what is indicated above. Make sure that both are specific to your server and key set-up.
Copy the file to the backup medium and verify the copy.
Store the backup in a secure, off-site location.