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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
Media |
Clear |
Sanitize |
Magnetic Tape1 |
Type I |
a or b |
a, b, or m |
Type II |
a or b |
b or m |
Type III |
a or b |
m |
Magnetic Disk |
Bernoullis |
a, b, or c |
m |
Floppies |
a, b, or c |
m |
Non-Removable Rigid Disk |
c |
a, b, d , or m |
Removable Rigid Disk |
a, b, or c |
a, b, d , or m |
Optical Disk |
Read Many, Write Many |
c |
m |
Read Only |
|
m, n |
Write Once, Read Many (Worm) |
|
m, n |
Memory |
Dynamic Random Access memory (DRAM) |
c or g |
c, g, or m |
Electronically Alterable PROM (EAPROM) |
i |
j or m |
Electronically Erasable PROM (EEPROM) |
i |
h or m |
Erasable Programmable (ROM (EPROM) |
k |
l, then c, or m |
Flash EPROM (FEPROM) |
i |
c then i, or m |
Programmable ROM (PROM) |
c |
m |
Magnetic Bubble Memory |
c |
a, b, c, or m |
Magnetic Core Memory |
c |
a, b, e, or m |
Magnetic Plated Wire |
c |
c and f, or m |
Magnetic Resistive Memory |
c |
m |
Nonvolatile RAM (NOVRAM) |
c or g |
c, g, or m |
Read Only Memory ROM |
|
m |
Static Random Access Memory (SRAM) |
c or g |
c and f, g, or m |
Equipment |
Cathode Ray Tube (CRT) |
g |
q |
Printers |
Impact |
g |
p then g |
Laser |
g |
o then g |
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 regarding clearing and
sanitizing security standard
DoD 5220.22-M see US Defence Security Service Web Site
(Chapter 8).
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