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From: 3ksnn64@pur-ee.UUCP (Joe Cychosz)
Newsgroups: sci.crypt
Subject: Re: Erasing magnetic media
Message-ID: <6964@pur-ee.UUCP>
Date: Mon, 2-Nov-87 14:29:22 EST
Article-I.D.: pur-ee.6964
Posted: Mon Nov  2 14:29:22 1987
Date-Received: Fri, 6-Nov-87 23:21:16 EST
References: <7566@reed.UUCP> <1175@cup.portal.com>
Reply-To: 3ksnn64@pur-ee.UUCP (Joe Cychosz)
Organization: Purdue University Engineering Computer Network
Lines: 11

In article <1175@cup.portal.com> Kenneth_R_Jongsma@cup.portal.com writes:
>Others may be interested.... The actual requirement is that the media
>be written with at least 100 alternating 1/0 bits. i.e 11111 00000 11111,
>etc...  Some media cannot be declassified. If memory serves, the old (still
>in use in the Minuteman system) core memory had to be destroyed.


I believe that once a media has been used for classified data, it can not
be re-used for unclassified data.  To dispose of, it must be destroyed.
It is quite easy (given the proper equipment) to recover information that
has be written over several times.