encryption is probably your best bet.
Examples:
T r u e C r y p t
AxCrypt File Encryption for Windows
Olaf L
August 12, 2013 at 6:32 am
You can install Folder Password Expert USB right on the external drive and set a password on your backup folder. You can download free trial from http://www.folder-password-expert.com/usb.html
Depending on the backup software you are using, you can probably assign a password to encrypt the backups you are making. If you don't want to go that route, one of the easier ways to do this would be to use TrueCrypt to encrypt the entire drive.
Link http://www.newsoftwares.net/download/folderlock7-en/fol...
used and tested folder Lock Software
encryption is probably your best bet.
Examples:
T r u e C r y p t
AxCrypt File Encryption for Windows
You can install Folder Password Expert USB right on the external drive and set a password on your backup folder. You can download free trial from http://www.folder-password-expert.com/usb.html
How To Password Protect Your USB Stick: 3 Easy Ways
http://www.makeuseof.com/tag/how-to-password-protect-your-usb-stick-3-easy-ways/
miTracker File Secure Free
http://www.mitracker.com/file-secure-free.html
How to Turn Windows 7 BitLocker On or Off for Internal Data Hard Drives
http://www.sevenforums.com/tutorials/4924-bitlocker-drive-encryption-internal-data-hard-drives-turn-off.html
What is the BitLocker To Go Reader?
http://windows.microsoft.com/en-US/Windows7/what-is-the-bitlocker-to-go-reader
You can use Folder Lock Lite software to protect the backup folder or LocK-A-FoLdeR.
Also,have a look at some of the suggestions provided by Microsoft Community which suggests using Truecrypt,BitLocker etc.
Try this, it has plenty of options including external drive lockup:
http://www.pcworld.com/article/257818/password_protect_your_files_folders_and_drives_with_file_secure_free.html
Depending on the backup software you are using, you can probably assign a password to encrypt the backups you are making. If you don't want to go that route, one of the easier ways to do this would be to use TrueCrypt to encrypt the entire drive.