Hard Disk Wiping and the Secure Removal of Data It is important
for businesses to recycle their computers, but have you thought
about what happens to the data on your computer when it is
collected?
How sensitive is the data stored on your hard disk? If you are
donating equipment to a recycler, you need to ensure that their
data removal procedures operate to a high standard.
A recycler needs to honour the requirements of the Data
Protection Act 1998, in summary:
To treat all data obtained from a donation as confidential To
use appropriate methods to securely destroy all data Notify the
donor as soon as possible if any unauthorised use or disclosure
of the data is made
How Do You Securely Remove Data? If a hard disk is formatted,
this is not a secure way to wipe data! This method has inherent
limitations, as only the file allocation tables and the pointers
to the data (that render the data inaccessible) are destroyed.
The data on the remainder of the drive is not destroyed, and the
inaccessible data is easily retrievable. There are many free
programs available on the internet to recover data from a
formatted drive.
Best Practice: A Recycler should use a piece of software which
will:
run from a bootable floppy report the actual hard disk capacity
(the same reading as the BIOS and label on the HD) overwrite a
single character pattern to the entire HD produce a report that
all areas have been overwritten report any bad or unusable
sectors that cannot be overwritten verify successful erasure The
key point here is that the hard disk is actually overwritten
with new data – ie. 10101010 This ensures that your old data
cannot be retrieved.
The Security Levels: In order for a disk to be wiped to High
Security Standards, such as Military Of Defense standard, the
hard disk is overwritten several times, for instance:
Perform 3 overwrite cycles to all areas (where each cycle will
be a single pattern, followed by its complement), and a final
overwrite with a random character pattern (ie. A total of 7
overwrites) – verification of successful erasure should then be
carried out for all Hard Disks.
How Do You Erase Data From A Hard Disk That No Longer Works? The
simplest way to ensure this is to destroy the Hard Disk.
Recyclers have many different methods for this, but an example
is to drill a hole through the disk, just off centre.
Summary Before you allow your computer equipment to be
collected, ensure you check the recyclers’ procedures for the
secure removal of data from your hard disks. Most recyclers will
also provide some form of report after the collection to
guarantee the data from your hard disks was securely removed.
About the author:
Lee Sykes operates the online WEEE Recycling Directory (Waste
Electrical & Electronic Equipment)
A free service where you can search for Computer Recycling in
your area, post a tender and request a Collection of Computer
Equipment, as well as provide businesses information regarding
how to comply with the WEEE Directive.
http://www.weeedirectory.com