Throwing out your old

computer? Think again. It’s time to get out your pickaxe...



Never in history has so much information been produced by so many people. We are swamped by electronic data, a tidal wave of gigabytes. Indeed, the world is probably producing more recorded information every second than it did in the entire 19th century.

With so much data - a stream of binary digits that includes everything from your holiday photos to your bank details to every email you and everyone else on Earth has ever written - it is not surprising that some of it often goes missing.

We have all heard of the hapless civil servants who leave laptops and memory sticks containing our personal details on trains or in taxis. But what few people realise is just how easy it is to recover deleted data from old computers - and the implications of this fact.

It's crunch time: Could it be time to bash up the old computer to save yourself from the Cyber-gangsters?



Because, unfortunately, a growing number of criminals realise this all too well - and an illicit industry has grown up 'mining' data, such as banking passwords and credit card numbers, addresses and details from people's CVs in discarded computers . These details are then sold on to unscrupulous people who can make good use of them.

'People are going to auctions, buying cheap second-hand PCs, ripping out the hard drives and selling them to criminals in Nigeria,' says Steve Whitehead, a computer expert who specialises in the safe storage and destruction of computer files.





This month, consumer magazine Which? Computing reports that it managed to recover 22,000 'deleted' files from eight computers it bought on eBay.

One Which? reader, Alexander Skipworth, was emailed by a crook from Latvia who had gained access to his old hard-drive; he had obtained from it not only Mr Skipworth's email address, but also his bank and mortgage details.

He emailed a personal photograph contained on the disk as proof and demanded money with menaces.

Mr Skipworth had, wrongly, been told the drive was erased after it was replaced by the computer manufacturer.

Hackers can access all sorts of information from your old computer - from bank details to every e-mail you have ever sent



As we trust more and more of our lives to our computers, criminals are having a field day. Think about it: a typical PC hard disk drive - a thin aluminium or glass magnetic-coated platter 31/2in across, which spins at anything up to 10,000 revolutions per minute and which is 'read' by a tiny stylus - can store an extraordinary 200 gigabytes of data.

That means you can store several million photos, whole libraries of books, movies and endless music tracks - not to mention thousands of supposedly private emails and passwords.

Disks of even larger capacity - up to a whopping one terabyte (1,000 gigabytes) - are common; these are enough to record, potentially, just about every conceivable detail of your life and the lives of everyone you know.

Computer disks (and other storage media, such as flash memory sticks) are not only extremely efficient storage devices, but they are also cheap - throwaway cheap.

A few decades ago, this sort of memory storage cost millions of pounds; now you can pay £50 for a new hard drive with more capacity than Nasa had at its disposal when it first went to the Moon.

Thanks to this, we upgrade our computers regularly - typically every three years. This means that, in Britain, several million old PCs and Macs are thrown away, sold, recycled or donated to charity every year.

Thousands of these machines are simply discarded without any attempt made to delete the files on them. The information on these old computers is freely available to anyone who gets hold of the machine. And even if we make an effort to delete our old files, the chances are they are still there.



Most people assume that if you delete a file from your computer's memory and then empty the 'wastebasket' that is on your desktop (and maybe run a 'disk clean-up' for good measure), the file is gone for good.

Not so. In fact, when you 'delete' a file from your PC, what you are doing is not erasing the file itself, but simply the reference to it on the hard disk.

The file itself is still there (until it is written over) and can be recovered with the right software. 'It's a bit like ripping the index from a book. The actual pages and text are still there,' says Whitehead.

These 'deleted' files can be recovered easily using proprietary file recovery software. Even erasing the whole operating system (eg Windows) still leaves the files intact.

You can go a step further: delete the files you want to erase, empty the recycle bin, download a huge file which fills the disk and overwrites the space taken up by the old files - and then delete that.

But even then, when your old files have been overwritten with new files, 'ghosts' of the old data may remain on the hard drive.

Computer disks use a magnetic medium to store information and, like magnetic tape, completely erasing all traces of what was on it is almost impossible.

Military-spec file-destroyers exist: these overwrite the old files five times in an attempt to obliterate all traces of what was on the disk.

But even then there remains the possibility that really determined hackers could gain access to snippets of surviving information.

How can you make sure this does not happen? There are special programs out there which claim to completely destroy files.

If you want to keep your hard disk intact and preserve the valuable software on it (perhaps if you are giving your computer to a friend), you can use a data-shredding program, such as Digital File Shredder from StompSoft, for around £20.

But if you want to be really sure, you will have to resort to violence.

Even this is surprisingly difficult. Hard disks are robust devices and though it is easy to destroy the sensitive electronics and the stylus mechanism, the disk itself is quite hard to destroy completely. Which? recommends a hammer; the Pentagon suggests putting the whole thing in a metal-mulcher.

Here are the ways I tried to make sure that these hard disks really were dead and buried ...

METHOD ONE: PICKAXE

If in doubt, use brute force. Hard disks are encased in a tough metal box, but even so this proves no match for a pickaxe - the method preferred by Steve Whitehead's employer PHL when really sensitive data is involved.

'We had a disk come in with thousands of credit card numbers on it,' he says. 'There was only one solution - take it out into the yard and smash it.'

EASE/COST: 10/10 - though be careful not to do yourself an injury.

EFFICACY: 8/10 - even though I gave the drive what I thought was a good battering, the platter inside was merely dented and a bit mangled.

I am not entirely convinced that there aren't experts who would be able to recover something from it, though such a job would be way beyond the capabilities of most criminal hackers.

A smaller hammer plus a chisel would perhaps make a better job of smashing the unit completely.

METHOD TWO: DRILL

THIS is recommended by the American magazine Popular Mechanics. Drill at least two holes through the disk itself and the platter will never spin again.

Better still, then take an angle grinder to the mirror-finish surface of the disk, the magnetic layer which stores the information.

EASE/COST: 6/10 - you need a powerful drill to get through the metal components, a strong vice in which to hold the drive unit and the procedure is potentially dangerous as parts could shatter. You MUST wear eye protection.

EFFICACY: 10/10 - if you drill enough holes, your data will be reduced to a pile of swarf. Follow up with a good grinding and maybe the hammer as well and your disk is toast.

METHOD THREE: CAR

Position the hard drive on a hard surface. Drive over it.

EASE/COST: 10/10.

EFFICACY: 0/10 - these units are so tough you'd need a traction engine to do much damage. You could probably run over most hard drives, plug them straight back into your computer - and they would run.

METHOD FOUR: FIRE AND WATER

Place the hard drive in a vice and blast it with a blowtorch. I submitted an old hard drive to 20 minutes of extreme thermal torture until it was glowing red hot.

Serious action: Taking a blowtorch to your old computer would blast away the chances of fraud



I then plunged it into a bucket of cold water hoping the shock would shatter any intact components.

EASE/COST: 2/10 - you need a blowtorch, goggles and somewhere safe to do this. Not recommended at home.

EFFICACY: 6/10 - astonishingly, though the outside casing of the hard drive was a charred mess and the electronics were fried, the shiny platter itself seemed completely undamaged.