Shredding my mac

[KooBrewoP]

I am selling my power book, and because i had all my bank details, passwords etc on it, i want to scrub the hard drive. My question is what software should i use?

someone also told me that 10.3 could do this, but i cant seem to work out if this is true. :o

[superbovine]

finder->secure empty trash

http://download.com.com/3120-20-0.html?qt=secure+delete&tg=dl-2003&search.x=18&search.y=8

[KooBrewoP]

I know how to securely empty the trash, but i wanted to know if OSX has a way of scrubbing the whole hard drive not just the trash.

[wrldwzrd89]

I know how to securely empty the trash, but i wanted to know if OSX has a way of scrubbing the whole hard drive not just the trash.
Yes - insert the Mac OS X boot/install CD, boot the Mac from it, select "Open Disk Utility" from the File menu, then choose "zero all data" in the format options. If you want to make it even more secure, check "8-way random write format" also. It will take MUCH longer to format the disk this way, but it will wipe out all your data with little chance of recovery, which is what you wanted.

[Macmaniac]

There are utilities like Super Scrubber which write random 0's and 1's on your HD, or in Panther you can 0 your HD making it nothing but zeros, that should destory your data.

[PlaceofDis]

the "eight way random" method is the best way to do this using 10.3, as mentioned it will take a LOT longer than simply erasing your disc. even "zeroing" your disc takes a lot longer (ive done it) but it is the best way to ensure all your data has been completely overwritten

[kidA]

just so you know, the only ways to positively get rid of all data and make a hard drive 100% unrecoverable are to 1) run it by a huge powerful magnet. or 2) physically smash it to pieces. unfortunately, both of these methods render the HD unusable as well. with any sort of overwriting methods, there is always a chance to recover something for someone who really knows what they're doing. that said, those chances are very very slim. the 8-way random write format is probably the best way. it takes a long long time, but security is your main concern. so it's definitely worth it, IMO.

[jimjiminyjim]

just so you know, the only ways to positively get rid of all data and make a hard drive 100% unrecoverable are to 1) run it by a huge powerful magnet. or 2) physically smash it to pieces. unfortunately, both of these methods render the HD unusable as well. with any sort of overwriting methods, there is always a chance to recover something for someone who really knows what they're doing. that said, those chances are very very slim. the 8-way random write format is probably the best way. it takes a long long time, but security is your main concern. so it's definitely worth it, IMO.

How can anything be recovered if the entire drive is re-written to zero's? With my rudimentary understanding, this makes absolutely no sense.

[zimv20]

How can anything be recovered if the entire drive is re-written to zero's? With my rudimentary understanding, this makes absolutely no sense.
i can't claim to understand the methods, but the NSA has them (probably the FBI and CIA, too)

[raptorhigh]

Don't think of a bit on a hard drive as a on/off switch. The tiny magnetic bits can't completely go from one extreme (on) to another (off). So when you remove the charge from specific bit (go from 1 -> 0) you will have a residual leftover. That is theoretically how government agencies pull data off of zeroed drives. A lot of high secruity agencies rewrite random data many times, THEN physically destroy.

That said, if you do the disk utility thing, you will be fine. A criminal will not have the resources to retrieve that info, and will go on to the next drive.

[Wes]

Last year my Comp Sci teacher told me that MI5 can not retreive data that has been re-written more than 9 times over but maybe they have improved their technique now.

[GovornorPhatt]

By searching on Version Tracker (http://versiontracker.com/php/search.php?mode=basic&action=search&str=shredder&plt%5B%5D=macosx&x=13&y=8), I found sevelal shareware and commercial utilites to do what has been described in this thread.

[superbovine]

Last year my Comp Sci teacher told me that MI5 can not retreive data that has been re-written more than 9 times over but maybe they have improved their technique now.

supposedly the with physical examination of the platter you can recover up to 14 times. I think that invovles and electron microscope though ;)

[jimjiminyjim]

This must answer your question KooBrewoP... If you think that the purchaser is a pretty smart person willing to take a lot of time to examine your hard drive with an electron microscope, overwrite the data at least 14 times. If you just want to prevent data recovery software from finding the data, use the zero all data/random overwrite features in the OS X Utility.

I provide no guarantee with this recommendation. It is based solely on the reading of this forum... :)