Declassifying some media.

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2 total messages Started by James T. McCartney III - DTN 381... Wed, 04 Nov 1987 18:00

#3868

Author: James T. McCartney III - DTN 381...
Date: Wed, 04 Nov 1987 18:00

11 lines
1127 bytes

 
> I am interested in 'Why' 100 alternate 1/0 writes will not declassify some
> media.  It seems to me that after 5 or so random 1/0 writes the original
> data would be so far gone that retreival by any means is impossible.
 
The reasons for this are known and are specified in the TEMPEST regulations
which describe how classified electonic and magnetic media must be handled.
This document is also classified, thus it can't be discussed in an open forum.
If you are interested and have a need to know, contact you installation 
security officer and they can provide details.

Re: Declassifying some media.

#3881

Author: aglew
Date: Sat, 07 Nov 1987 04:39

12 lines
1036 bytes

..> Declassifying electronic media

Writing alnernating bands of zeroes and ones a few times might be a good start.
101010... 11001100... 1111000011110000....

Next, one would want to write a random bit pattern over the data you want
to declassify.

But even then you have to worry about jitter, about the analog bit patterns
not quite matching up with the original when overwriting. Plus effects that
might come from the tape running a bit slower/faster...

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