When you hear the phrase data security, chances are you’d instinctively think of online security, and with good cause. With the proliferation of online banking and online shopping, security is vitally important and you’d be right to give it the attention it deserves.

However, it’s not only when your sensitive data flows across the Internet that it’s at risk. While it receives much less attention, the data stored on your hard disk can also pose a security risk as we’re about to see.

Elsewhere in this issue (see page xxx) we provide guidance on how to securely delete data on a disk so that it can’t be recovered using un-delete utilities. This way you can sell your PC, donate it to a charity, or dispose of it at a recycling centre without any concerns that someone might be able to read your financial details, passwords or personal emails.

There are other ways that you may be separated from your PC, though, and in these cases you won’t have taken any precautions such as securely deleting files. If you leave your laptop on a train or someone steals your PC in a burglary, it’s not only deleted files that you need to be concerned about – the files you’re using on a day-to-day basis will also be an open book to those with unscrupulous intentions.

The solution is to encrypt the files you don't want anyone else to see. Today, encryption algorithms are so sophisticated that it would take years of computing power – quite literally – for an unauthorised person to crack the code. However, the traditional approach to encryption was so much hassle that most people didn’t bother. After all, how would you feel about having to decrypt your home finances workbook before you could open it in Excel and then, each time you saved it, having to encrypt it again?

Fortunately the latest generation of hard disk encryption tools makes the process transparent, so there's really no excuse not to use it. Here we’ll show you how to use a free utility called Cryptainer LE.

As we’re about to see, with Cryptainer LE, encrypting and decrypting individual files is a thing of the past. Instead, all you need to do is provide a password each time you start your PC to make all your encrypted files accessible. What’s more, shutting down your PC normally is all it then takes to keep your personal data from prying eyes.

How to install and use Cryptainer LE

1. The first time you run Cryptainer LE the ‘Specify Cryptainer Volume Details’ window appears. You need to choose the size of the volume (i.e. the total storage required for all your encrypted files), and a password (twice) before clicking on ‘Proceed to Create Volume’. Cryptainer now creates and loads an encrypted volume which appears as a virtual disk drive.

Create an encrypted volume

2. To see what’s happened, start Windows Explorer and look at the available disks. In addition to the usual ones such as your hard disk (C:), a CD or DVD drive (probably D:), and perhaps a flash drive, you’ll see a disk referred to as Cryptainer. It’s empty but you can move into it any files you want to be protected, so drag a few to it now.

Copy files to the virtual disk

3. Return to Cryptainer LE and you’ll notice that the main window shows any folders you’ve created within the Cryptainer virtual disk and the files that you’ve copied into this encrypted volume. These files are fully accessible, by all the usual methods. You can work on them as usual, editing, creating and viewing files in this new disk in the knowledge that they’re totally secure.


4. When you shut down your computer, the Cryptainer volume will be unloaded automatically so that its contents can’t be read but you can also unload it if you’re going to be leaving your PC for a while. Simply click on the Unload button and you’ll discover, if you look in Windows Explorer, that the Cryptainer volume is no longer visible.

Load and unload volume

5. When you next start your PC, the Cryptainer volume won't be available since it was unloaded when Windows was shut down. The actual file you specified in Step 1 that contains the data is still there but it’s encrypted so any attempt to read it will just reveal garbage. To load the volume, click on the Load icon in Cryptainer and supply your password.

Enter password

6. You can also encrypt individual files for emailing. Select ‘Encrypt File to Send by Email…’ from the Tools menu, select the file and a password before clicking on ‘Encrypt File…’. The encrypted file will have the original filename but with ‘.sit’ added to the end. The recipient needs to have Cryptainer installed and must select ‘Decrypt File…’ from the Tools menu, select the encrypted file, and enter the password and a name for the decrypted file.

Encrypt emails

Encrypt your Instant Messages

With Cryptainer, the most sensitive files on your hard disk are protected by encryption and you can also encrypt files before sending them via email. Your bank and major online stores will use encryption for transmitting your personal data across the Internet but this still leaves one important sphere of your digital life that might unprotected.

Depending on your choice of service, should anyone hack into your instant messaging, your conversation would be clear to see. Fortunately, for those occasions when you want to transmit sensitive data via instant messaging, services are available providing fully encrypted traffic that will be meaningless to an eaves-dropper.

In all fairness, while not universal, many instant messages services do employ encryption and for most people that will be perfectly adequate. For a list of which clients have built-in encryption, see Wikipedia's features comparison. Note that some of the popular clients such as Windows Live Messenger, Yahoo! Messenger, Google Talk and Empathy do not have encryption.

However, if you strive a greater level of security, there are instant messaging clients that have been designed from the ground up specifically as security products. In addition to providing encryption, some provide a whole host of additional security related services (for example, a means of ensuring that you know for certain who you’re chatting with) and often they provide a peer-to-peer link so you traffic doesn’t pass through online servers.

X-IM is one such free service although it uses a server rather providing a peer-to-peer connection. BitWise IM is a peer-to-peer service but the free BitWise Personal doesn’t provide identify verification, something you only get with BitWise Plus.