Fujitsu ScanSnap N1800 Operator's Manual page 33

Key regeneration
When the user data store is cleared from the scanner, the old cipher key is deleted
and a new cipher key is generated. This totally eliminates the possibility of access
to any user data remaining in the free disk space. The free disk space can be also
overwritten with meaningless random data.
There is no input pathway to the scanner for files via external memory media, and input
pathways of files via the network are limited to the minimum. Security patches are
provided to protect the scanner against virus attacks. Taking these measures enables the
scanner to be protected against virus infection.
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