Set Up an Encrypted Mirror Database
Applies To: SQL Server 2016
To enable automatic decryption of the database master key of a mirror database, you must provide the password used to encrypt the master key to the mirror server instance. SQL Server 2005 and later versions include mechanisms to transfer the password. Use sp_control_dbmasterkey_password to create a credential for the database master key before you start database mirroring. You must repeat this process for every database that will be mirrored. For more information, see sp_control_dbmasterkey_password (Transact-SQL).