In article <[log in to unmask]>, dated Mon, 14 Dec
1998 at 11:40:42, [log in to unmask] writes
>Both are right, surely. 'Deleted' data may or may not be overwritten by future
>writes, depending on how much of the disk is free and on other OS factors
>beyond my ken. Normal reformatting, which is merely erasure of the FATs and ?
>root directory of the HD certainly leaves recoverable data littered all over
>it. Security requires also running a program such as 'WipeDisk' (used to be
>available in Norton utilities) which writes zeroes all over the disk so there
>is no information left on it at all. (WipeFile does same for a particular
>file,
>but I wonder if it erases temporary files related to its production (see
>below)).
There are even companies that will attempt to retrieve overwritten data
with some degree of success. It's apparently something to do with
residual magnetism, i.e. the original data is still there although with
such a weak 'magnetic signature' it would normally be undetected by the
disk heads.
Those whose personal safety may depend on data being secure will go to
extraordinary lengths in ensuring security by such methods as encrypting
(with a very secure algorithm) whole disk partitions and/or reformatting
disks on a daily basis. Also, as you imply there are many OS and
application dependent temporary areas which may retain information long
after the primary data is removed and/or secured. The MS Windows swap
file is a good example. Security is relative. It's important to assess
the real risk and impact of data being compromised otherwise you may end
up expending more time and effort on securing that data than you do
actually using it!
Chris
--
Chris Salter (Vice Chairman) Lincolnshire Post-Polio Network
Registered Charity No. 1064177
<URL:http://www.zynet.co.uk/ott/polio/lincolnshire/>
Web Site & Vice Chairman Email: [log in to unmask]
Honorary Secretary Email: [log in to unmask]
Member of the British Healthcare Internet Association
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