Download Microsoft® SQL Server® Backup to Microsoft Azure®Tool and install it on the server where you want to encrypt database back.
Download link : http://www.microsoft.com/en-sg/download/details.aspx?id=40740
After the installation is successfully navigate to services.msc (Microsoft SQL Server backup to Windows Azure Tool) Service.The service installs with a default login , change it to the correct user and start the service.
Browse the tool from Start (Programs)
Lets Configure the Tool
Specify the backup location or all paths.Lets specify a path for demo
Click Next and choose option local storage
Click Next (Currently AES-256 Encryption is available with/without Compression) and click Finish.
To test , lets run the backup from SQL Server Management Studio, You don’t need to do any configuration changes in SQL Server Configuration.
If the backup is in single file , single encrypted file will be generated, if backup is done in multiple stripes , encryption will happen for each file as backup progresses.