Data and Hard Drive Wipe Services

Computer Disposal Advice - Data Erase and Wipe

Deleting files from your hard drive is not a secure method of erasure.  It can take a very long time to trawl your hard drive erasing all the data and documents you need to.  If you use the delete button on your computer all it is doing is deleting the link or shortcut to a file so it can’t be seen.  The point is that the file is still there but isn’t easily accessible or visible. There are all sorts of utility programmes designed  to ‘recover’ the files that are still in place on your hard drive which almost anyone can use.

A slightly more thorough option is to format or reformat the hard drive.  Like deleting, formatting will wipe the links to files from the operating system to files on the hard drive but it still won’t erase the files themselves.  It makes them more difficult to find by erasing entries in the address tables. One of the dangers is that users sometimes unintentionally format a drive so there is software designed to recover files in this situation. In these genuine cases, its clearly of benefit to be able to get back lost data and files.  It remains the case that fraudsters could use the same software to view confidential  information from a second hand computer or one which has been donated to a charity.   

The key point is that formatting is not a secure method to totally wipe all files from your PC.  There are important decisions to be made about hard disk erasure.  A disk format is much better that none at all and your decision will depend on the confidentiality and type of data you save on your data storage devices.  If you elect to wipe the hard drive using formatting – a full format is preferable to a quick format.

One of the most secure methods of data destruction is Disk Wiping.
The phrase disk wiping can refer to data on hard drives as well as other data storage media such as CDs, RAIDs, thumb drives and DVDs. Disk wiping is a secure way of making sure that information, including company and personally licensed application on your servers and workstations and media is permanently erased so it cannot be recovered.  Data wiping should be carried out before IT equipment is recycled or given to other organisations such as schools.  Decent data wiping software will overwrite the hard drives a number of times replacing all the data bits on the drive.  This makes it impossible for data recovery applications to rebuild files.  Data on the entire drive is erased. The more times the data wiping software is used the more secure is processed. Once data wiping is complete the hard drive will be rewritten with a zero or a one in all data storage locations including all hard drive sectors, the partition table and the master boot record.  The more times the software overwrites the disk, the longer it takes.

There are several standard or recommendations that apply to data wiping.  The US government standard (DoD 5220.22-M ) recommends three passes for medium levels of security and up to six passes for the top level of protection.  What can take time is that one ‘pass’ can actually involve two data wipes over the whole drive – one to insert ‘1’ data bits and another to inserts ‘0’ s on the drive surface.  Some applications then write a unique code on the drive to verify the software has worked correctly.  All this takes time.

Mandatory Requirement 45
Departments and Agencies must ensure that all media used for storing or processing protectively marked or otherwise sensitive information must be disposed of or sanitised in accordance with HMG IA Standard No.5 – Secure Sanitisation of Protectively Marked or Sensitive Information.

HMG Security Policy Framework V1.0 December 2008 (SPF 70)