If you've owned a computer for any length of time at all, you've probably filled it up with photos, music, and files you don't really want to lose. And like most people, you don't have a backup.

The recent natural disasters here in the US (earthquakes, tornados and wildfires, oh my!) have finally prompted me to start backing my data up to a location off my property so that I can do a total restore in case my place burns down. Here's how I'm doing it.

I went out and bought a 3TB drive (about $140 after tax) to hold my data. I'll put a copy of all my data on it, and leave it at the office. I'll bring it home every now and again for refreshing. I could have bought 2 of them and alternated them, as well.

Leaving it at the office means it would be outside my direct control and I don't want someone snooping around in my files. So I partitioned the drive into a small 100GB partition, and the rest (~2.5 TB after converting to binary) I'll use for my data.

On the small partition I put downloaded copies of Truecrypt (www.truecrypt.org), which is a very strong encryption program (used by humanitarian workers to protect data from totalitarian governments). This way I'll have a copy of the program on the drive to reinstall from scratch.

I went ahead and installed Truecrypt on my Mac (works on Windows too), and walked through it's encrypted volume creation process. You have 2 choices when creating the encrypted volume - you can convert the entire partition into an encrypted volume, or create a very large file and use it as your volume. Because the multi-terabyte drives are new, Truecrypt can't support them for an encrypted volume yet, so I had to create an encrypted file to fill the 2.5 TB partition.

You will need to pick a passphrase to use for the volume. You'll want a sentence that you can remember that is longer than 25 characters but less than 64 characters. Just using "password" isn't very secure, as it's only 8 characters, and could be broken in just a few seconds because it's a dictionary word. If you use a sentence, the time to break the encryption goes up significantly (as in: centuries to break). So use a sentence or phrase that you will remember. Project Gutenberg (www.gutenberg.org) has a lot of classic literature to help you pick something memorable.

Truecrypt needs a source of random data in order to create a good encryption key, so when it asks, move your mouse around a lot, in fits and starts. Then click the create button, and it will start writing out the storage file. On my 2.5 TB drive, this process took 37 hours.

When it completes, Truecrypt will mount the drive, and you'll have another drive letter (on Windows) or volume (Mac) that you can copy your files to. Leave Truecrypt running until you're done.

When you are finished, unmount the virtual drive using Truecrypt. Then dismount the 2.5 TB drive (eject it) using the operating system, and take it to your off-site location (office, safety-deposit box, friend's house, etc). Since the data is encrypted, the worst that could happen is the drive itself could be stolen, but the data on it will not be able to be read.

Be aware that Truecrypt and having encrypted data is illegal in some Western countries (UK, France, Italy, South Korea) as well as the usual developing countries (China, Ukraine, etc). Also, you cannot boot from a Truecrypt volume, so you can't protect an entire laptop -- only the data you place in the Truecrypt volume.

When you want to refresh the data on the drive, bring it home and run Truecrypt, mounting the encrypted volume (you will need to supply your passphrase). Truecrypt will then present you will a virtual drive that you can copy your new and updated files to.

Truecrypt will work on a memory key too. So if you want to experiment with an old 2 GB thumb drive, you can do this before spending money on an external drive.

Chip H.