Wip­ing your com­puter

HOW TO SAFELY GET RID OF OLD COM­PUT­ING DE­VICES.

TechLife Australia - - WELCOME - [ NATHAN TAY­LOR ]

GET­TING RID OF an old PC or mo­bile de­vice can be re­mark­ably fraught. Whether you’re sell­ing, gift­ing, or just throw­ing the de­vice out, you will need to take steps to prop­erly and se­curely clean the de­vice be­fore you do so. You don’t want to be­come one of those cau­tion­ary tales about a per­son who had all their data and per­sonal files pub­lished on­line be­cause you didn’t bother to prop­erly de­stroy your data be­fore get­ting rid of the de­vice!

Some peo­ple take this process to ex­tremis, phys­i­cally de­stroy­ing hard drives with sledge­ham­mers and drills to make sure that no­body can re­trieve data. This month we’re go­ing to look at some less rad­i­cal ap­proaches that don’t re­quire phys­i­cal de­struc­tion of your equip­ment.

ON FILE SYS­TEMS (OR WHY THIS IS IM­POR­TANT)

As a start­ing point, you should recog­nise that sim­ply delet­ing files is not enough. Deleted files can very of­ten be re­cov­ered – which is handy when you ac­ci­den­tally delete an im­por­tant file, but po­ten­tially dev­as­tat­ing if you have, let’s say, some “self por­traits” on a de­vice that you gave away.

What many peo­ple don’t re­alise is that delet­ing a file does not ac­tu­ally delete the file data; it just deletes its en­try in the file sys­tem.

To step back a bit, all a com­puter’s data stor­age hard­ware does is give the com­puter a place to store 1s and 0s. Your com­puter’s hard drive doesn’t tell the com­puter how to or­gan­ise or man­age that stor­age space. That’s where the file sys­tem comes in.

The de­vice’s file sys­tem or­gan­ises the stor­age space, serv­ing as a kind of di­rec­tory sys­tem for the raw stor­age space. It says, for ex­am­ple, “the file pro­gram.exe starts at byte num­ber 104595636 and ends at byte 124753625.”

When you delete the file pro­gram.exe, the com­put­ing de­vice doesn’t go and turn all those bytes to zero. It just deletes the en­try in the di­rec­tory, kind of like re­mov­ing a name from the White Pages. Un­til those bits are ac­tu­ally over­writ­ten, pro­gram.exe will re­main on the drive. Hid­den, but still there for some­one who knows how to look.

That’s why you have to do more than just delete files – you have to nuke them from or­bit.

WIP­ING AN­DROID

Mo­bile plat­forms, be­ing newer than PCs, have some ad­van­tages over Win­dows when it comes to file pro­tec­tion. For a start, on nearly all newer phones and tablets, en­cryp­tion is en­abled by de­fault. An en­crypted file sys­tem means that even if a hacker could ac­cess resid­ual data on a de­vice, it would be mean­ing­less gob­bledy­gook.

But there’s a ‘but’ here. Older An­droid de­vices are not en­crypted by de­fault. If you have a ver­sion of An­droid ear­lier than 6.0, there’s a chance that the phone or tablet is not en­crypted. Even if you have a newer ver­sion, it’s worth check­ing.

In An­droid, go to Set­tings->Se­cu­rity. Tap on En­crypt de­vice and en­able en­cryp­tion on the An­droid de­vice you want to get rid of, if it’s not al­ready en­abled. You can also en­crypt SD-cards.

If you’ve gift­ing or sell­ing the de­vice, there may be one more thing to do be­fore you’re ready to wipe the de­vice. In An­droid 5.0, Google in­tro­duced Fac­tory Re­set Pro­tec­tion (FRP), to stop thieves from steal­ing then wip­ing de­vices for re­sale. You’ll want to dis­able this – oth­er­wise the new owner will get a screen ask­ing for the pre­vi­ous owner’s (ie your) Google Ac­count de­tails.

FRP links your de­vice to your Google ac­count, so that af­ter a fac­tory re­set it will ask you to log in with your Google ac­count to en­able the de­vice. To dis­able FRP, you have to un­link the de­vice from your Google ac­count. In most de­vices, this will hap­pen as part of the Set­tings-based fac­tory re­set process, but to be sure you should go to Set­tings->Ac­counts (or Set­tings->Google on some de­vices) first and delete your Google ac­count from the de­vice. This will dis­able FRP.

Once you’ve en­crypted the de­vice and dis­abled FRP, you’re ready to run a wipe. Go to Set­tings->Backup & Re­set and se­lect the

WHAT MANY PEO­PLE DON’T RE­ALISE IS THAT DELET­ING A FILE DOES NOT AC­TU­ALLY DELETE THE FILE DATA; IT JUST DELETES ITS EN­TRY IN THE FILE SYS­TEM.

op­tion to per­form a Fac­tory re­set. You’ll get a warn­ing, and if you pro­ceed your de­vice should be clean.

Re­mem­ber to re­move your SD Card and SIM, and the An­droid is good as new.

WIP­ING IOS

Be­cause iOS de­vices are en­crypted by de­fault, and have no equiv­a­lent to Google’s Fac­tory Re­set Pro­tec­tion, the process for wip­ing an iOS de­vice is sim­ple. Make sure ev­ery­thing is backed up, then just go to Set­tings->Gen­eral>Re­set and tap on Erase all Con­tent and Set­tings. You’ll get a warn­ing page, then the de­vice will be com­pletely wiped. Re­move the SIM, and it’s ready to give away or throw away. Prop­erly clean­ing a Win­dows PC can be tricky. Win­dows is not en­crypted by de­fault, and its file sys­tem ac­tu­ally makes it rel­a­tively easy to re­cover deleted files. That’s why “shred­der” ap­pli­ca­tions are pop­u­lar – they do more than just delete the en­try in the file sys­tem – they over­write (of­ten mul­ti­ple times) the phys­i­cal stor­age space en­sur­ing that no re­cov­ery of files is pos­si­ble.

Win­dows 10’s Re­set Fea­ture (found in Set­tings->Up­date & Se­cu­rity->Re­cov­ery) does

not shred files. It will delete files if you choose the Re­move Ev­ery­thing op­tion, but those files could be re­cov­ered with an un­delete util­ity.

If you’re throw­ing away or sell­ing the PC, and you don’t care about hav­ing a work­ing in­stall of Win­dows on it, your best op­tion is a tool like Dban ( dban.org), a bootable util­ity that you can put on a flash drive or DVD disc. Other op­tions in­clude PC Disk Eraser ( www.

pcdiskeraser.com) and MHDD ( hd­dguru. com/soft­ware/2005.10.02-MHDD/).

To use these, tools, down­load the .ISO file from the app web­site. If you have a DVD burner, you can burn it to a disk just by right click­ing on it. If you want to put it on a USB stick, that’s a lit­tle more com­pli­cated: you’ll have to use a tool like Ru­fus ( ru­fus.ie) to cre­ate a bootable USB stick with the ISO file.

Then insert the disc or USB stick and re­boot your com­puter. Hope­fully, the app should run and you’ll be able to use it to prop­erly wipe the hard drive. If it doesn’t run, then you may have to go into your com­puter’s BIOS to change the com­puter’s boot or­der (you’ll have to con­sult the moth­er­board or de­vice maker’s guide on how to boot into the BIOS).

If the com­puter is a hand me down, and you want to keep a work­ing copy of Win­dows on it (and not have to com­pletely re­in­stall Win­dows from scratch on a wiped hard drive), then you have an­other op­tion: a Win­dows file shred­der app.

We like the free and open source Eraser ( source­forge.net/projects/eraser/), which you can use to delete and shred any per­sonal files on the com­puter. You have to choose which files you want to shred man­u­ally, but it both deletes the file and com­pre­hen­sively over­writes the hard drive to pre­vent re­cov­ery. It can also be used to shred any files in your re­cy­cle bin.

Use Eraser to delete ev­ery per­sonal file on the hard drive, in­clud­ing ev­ery­thing in your user folder.

Af­ter you’ve done that, you can then go and run the Win­dows Re­set tool (see above), which will re­store Win­dows to its fac­tory state. It should then be safe to pass on.

En­crypt the file sys­tem first.

Run a fac­tory re­set to wipe the de­vice.

Win­dows Re­set will delete your files, but it won’t shred them.

Dban is a bootable tool for eras­ing hard drives.

Eraser is a sim­ple and ef­fec­tive Win­dows tool for shred­ding files.

Re­set in iOS.

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