posted on January 18, 2003 05:52:51 AM new
If you've ever thought of selling your computers hard drive, or have done so in the past, you may want to read this article.
Cleaned out your personal files? Think again. MIT graduate student Simson Garfinkel holds one of the more than 100 used hard drives he bought, most of which still held personal and financial data from their previous owner.
posted on January 18, 2003 11:38:06 AM new
From that article: "The only sure way to erase a hard drive is to “squeeze” it: writing over the old information with new data — all zeros, for instance — at least once but preferably several times."
Yeah. But that's minimal protection. The Department of Defense reccomends a better procedure that runs a set of numbers six times across the hard drive from end to end (DoD 5220.22-M, National Industrial Security Program Operating Manual). Norton System Works has a program called "Wipe Info" that does just that.
I read last year, where someone at MIT was reccomending at least 16 times, as they had been able to recall traces of the original write up to then. Then, an article came out about the FBI being able to recover information that had been wiped that way up to 24 times!
Your bottom line is: take your old hard drives and floppy disks to a professional grinder and watch them while they grind your belongings into dust.
posted on January 18, 2003 11:59:47 AM new
Yes take them to a shop that has a grinder - but just borrow the demagnetizer that is used beside the machine and roll the drive around on both sides real well before discarding. The fields used are very intense and reverse themselves with the 60 HZ power cycle so it will change the magnetioc medias overwrite hundreds of times.
If that is not enough put it on the BBQ grill over a stack of charcoal and melt the sucker down to a puddle. If it has a steel case that will remnain but everything else will go.
I have a friend with a computer that has a brick of thermite over the hard drive in a ceramic tray. If you snoop it melts even the steel into a white hot molten ball.
posted on January 18, 2003 12:08:18 PM new
Linda - We should've stuck to paper! Remember how the computer was going to revolutionize all the paperwork? What a crock!
posted on January 18, 2003 09:25:27 PM new
There are lots of programs available to over-write data on a drive. You can do it to the free space on an in-use drive, not just one you want to pitch. These programs let you specify the number of overwrites and the type of gobbledeygook you want to overwrite with, either text or hexadecimal. Yes, forensic techs could probably recover parts of data left after some kinds of wiping, but it's difficult and expensive. For the average user, a DOD level wipe of 8 to 24 times using a program like WipeInfo, which comes with Norton Utilites by Symantec, will make files unrecoverable for all practical purposes. Another simple option, often overlooked in our quest for simplicity, is to keep your passwords, credit card numbers and bank account info somewhere else besides your computer...duh.....
posted on January 19, 2003 08:31:16 AM new
Thermite is Aluminum mixed with rust.
You can make an acceptable mix by mixing half and half. The metal shaving from a band saw that has been cutting aluminum. I got rust out of the bottom of 55 gal. drums that were storing scrap metal outside. All free.
Any metal oxide mixed with a reactive metal like aluminum or magnesium will work.
The trick is igniting it.
I use a magnesium ribbon stuck deep in the mix and the end beaten thin and wrapped around the filiment of a 12 vold stop light bulb with the glass cracked off. Ignites pretty reliably.
If you need to form it in a shape squirt a bit of glue in a few tablespoons of water and wet the powder. Then it will hold the shape when you mold it. You can mold it around your igniter and seal the whole thing up with any plastic base paint.
Testing it I set off a coffee can full of it and the baseball size ball of white hot steel went down through a 4 inch steel reinforced driveway like cutting butter. Took about 3 seconds for the whole can to fuse together and react completely. The aluminum sucks the oxygen out of the rust and you get iron aluminum oxide slag and mucho calories. Too hot to even look at directly.
Probably against some law to have even though it does not go boom. They used to use it to weld rail road track together. They'd clamp a ceramic mold around the two ends and burn this stuff in a funnel above and it would melt the ends and fill the gap. Then take the mold off and smooth it off.
We should've stuck to paper! Remember how the computer was going to revolutionize all the paperwork? What a crock!