Re: Hard Drive data security

[Atom 'Smasher' <atom () suspicious org>]

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>   I have a question about hard drive data security. The hard drive on my 
> notebook is failing and Dell is going to replace it. They are going to 
> take the old one with them. How can I securely remove the data from the 
> hard drive?
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there are several ways to do this, some good, some bad... i'm not going to 
attempt to cover all of the possibilities; i'll just mention what i'd do 
(i consider it to be good)... this assumes you're in a *nix environment.

install the drive on a computer that's running some flavor of *nix. don't 
mount the drive. let's say, hypothetically, the system sees at /dev/hd2. 
one way to write random garbage to the disk is:
        cat /dev/urandom > /dev/hd2

this will probably take a while and may slow everything down, but it's 
thoroughly wiping the disk.

repeat as necessary, based on what you perceive your threat model to be. 
if you're concerned about the drive showing up on ebay or a garage sale, 
wiping it once or twice should be fine. if you're concerned that a govt 
spy agency is taking interest in your data, wipe at least seven times.

i will point out the urandom is a CSPRNG, not a ~true~ RNG. this may be a 
concern to some in the tin-foil-hat crowd, and can be solved with:
        tail -f /dev/random > /dev/hd2

but that will take a *really* *long* time to fill up a disk.


        ...atom

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