How can I encrypt my iPhone backup in iTunes?
You can increase your iPhone backup security by encrypting backup files written to your computer during an iTunes syncing operation. This means that should your computer be lost or stolen, the backup files from your iPhone will be password protected. Contacts, location data, calendars and other sensitive information from your iPhone is stored in each backup file.
To encrypt your iPhone backups:
1. Open the iTunes application on your computer.
2. Connect your device to the computer via USB.
3. Click on the icon of your iPhone in the left menu under DEVICES.
4. Under the Summary tab -> Options -> check the box Encrypt iPhone backup.
5. You will be prompted for a password, enter it twice.
6. Click Set Password.
7. Backups will be encrypted from now on when you sync your iPhone.