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Standard DoD 5220.22-M
US Department of Defense in the clearing and sanitizing standard DoD
5220.22-M recommends the approach "Overwrite all addressable
locations with a character, its complement, then a random character and verify"
(see table with comments) for clearing and sanitizing information on a writable
media.
To conform this security standard in Active@ KillDisk Professional version
this approach has been implemented, i.e. one pass equals triple data
overwriting for the destruction of remains of sensitive data.
US Department of Defense 5220.22-M Clearing
and Sanitization Matrix
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Media
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Clear
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Sanitize
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Magnetic Tape1
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Type I
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a or b
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a, b, or m
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Type II
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a or b
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b or m
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Type III
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a or b
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m
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Magnetic Disk
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Bernoullis
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a, b, or c
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m
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Floppies
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a, b, or c
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m
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Non-Removable Rigid Disk
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c
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a, b, d , or m
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Removabel Rigid Disk
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a, b, or c
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a, b, d , or m
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Optical Disk
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Read Many, Write Many
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c
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m
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Read Only
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m, n
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Write Once, Read Many (Worm)
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m, n
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Memory
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Dynamic Random Access memory (DRAM)
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c or g
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c, g, or m
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Electronically Alterable PROM (EAPROM)
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i
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j or m
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Electronically Erasabel PROM (EEPROM)
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i
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h or m
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Erasable Programmable (ROM (EPROM)
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k
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l, then c, or m
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Flash EPROM (FEPROM)
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i
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c then i, or m
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Programmable ROM (PROM)
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c
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m
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Magnetic Bubble Memory
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c
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a, b, c, or m
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Magnetic Core Memory
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c
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a, b, e, or m
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Magnetic Plated Wire
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c
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c and f, or m
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Magnetic Resistive Memory
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c
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m
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Nonvolatile RAM (NOVRAM)
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c or g
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c, g, or m
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Read Only Memory ROM
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m
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Static Random Access Memory (SRAM)
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c or g
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c and f, g, or m
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Equipment
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Cahtode Ray Tube (CRT)
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g
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q
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Printers
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Impact
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g
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p then g
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Laser
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g
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o then g
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US Department of Defense 5220.22-M Clearing
and Sanitization Matrix
a. Degauss with a Type I degausser
b. Degauss with a Type II degausser.
c. Overwrite all addressable locations with a single character.
d. Overwrite all addressable locations with a character, its complement, then
a random character and verify. THIS METHOD IS NOT APPROVED FOR SANITIZING MEDIA
THAT CONTAINS TOP SECRET INFORMATION.
e. Overwrite all addressable locations with a character, its complement, then
a random character.
f. Each overwrite must reside in memory for a period longer than the
classified data resided.
g. Remove all power to include battery power.
h. Overwrite all locations with a random pattern, all locations with binary
zeros, all locations with binary ones.
i. Perform a full chip erase as per manufacturer's data sheets.
j. Perform i above, then c above, a total of three times.
k. Perform an ultraviolet erase according to manufacturer's recommendation.
l. Perform k above, but increase time by a factor of three.
m. Destroy - Disintegrate, incinerate, pulverize, shred, or melt.
n. Destruction required only if classified information is contained.
o. Run five pages of unclassified text (font test acceptable).
p. Ribbons must be destroyed. Platens must be cleaned.
q. Inspect and/or test screen surface for evidence of burned-in information.
If present, the cathode ray tube must be destroyed.
For more information regading clearing and sanitizing security standard DoD
5220.22-M see US Defence Security Service
Web Site (Chapter 8).
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