Table of Contents
Planning labels requires a general knowledge of site security, and specific
knowledge of the syntax of the
Study and outline your label encodings file
Make a label encodings file that enforces your site security policy.
Build an extensible
Create a file that can be modified without affecting existing label definitions.
How to Strategize for Labels
Allow time to build a correct
Building the encodings for a site and making the encodings correct
can be a time-consuming process. A system cannot be configured until the correct
label_encodings file is installed.
Know your site's security policy.
Many sites already have a security policy that was developed according to government methods. Commercial businesses, even businesses that do not have much experience in planning labeled security, can start by examining their goals for information protection. These goals can be used to make some common-sense decisions about how to use labels. If the company has developed legal requirements for labeling printed information and email, those guidelines are a good place to start.
For an example, see.
For more about setting up your site's security policy, see.
Study the U. S. government label encodings file.
The government's description of the file is in the: Defense Intelligence Agency document [DDS-2600-6216-93].
LOCAL DEFINITIONS section for
For suggestions and examples, see.
Finalize your encodings before installing Trusted Extensions.
label_encodings file on a running
system is risky. For more information, see the man page.
How to Plan the Encodings File
The following practices help create a correct
that can be safely extended later.
the security administrator role can later change the textual representation.
However, the integer and bit values cannot be changed without potentially
For ideas, see. For the procedure, see .
Leave room to add items.
Leave gaps when you number classifications.
For example, you could number classifications in increments of 10. The increments allow intermediate classifications to be added later.
Leave gaps in compartment bits.
Space compartment bit numbers for possible later additions.
Reserve some initial compartment bits for later definition.
If your site uses inverse compartments, see. To learn more about inverse compartments, see the DIA reference, .
Determine classifications for the site.
As described in, the total number of classification values that you can use is 254. Do not use classification 0.
The system treats a classification value of 10 as more security-sensitive than a classification value of 2. The textual representations are not used to determine security levels.
The same classification value cannot be assigned to different names. Each classification must be higher or lower, or disjoint, from any other classification. No two labels can evaluate to the same level.
A table can be used to plan classifications. For a completed example, see.
Decide on compartments.
Decide how data and programs are grouped. Decide whether any data or programs can be intermixed. For example, perhaps purchase order data should not be seen by programs that manage personnel files. Perhaps purchase order data should be accessible to programs that deal with shipment tracking problems.
At this point, do not consider users. Think in terms of what, not who.
Design the names.
WORDS in the
label_encodings file have two
forms: a mandatory long name and an optional short name. Short names can be
entered interchangeably with long names when labels are being specified.
Arrange the relationships.
One way to make this step easier is to use a large board and pieces of paper that are marked with your classifications and compartments. For an example, see. With this method, you can visualize the relationships and rearrange the pieces until they all fit together.
Unless you are creating a set of encodings that must be compatible with another organization's labels, you can assign any valid number as a compartment bit. Keep track of the numbers that you use and their relations to each other.
Decide which clearances to assign to which users.
You can use a table to plan clearances. For a completed example, see.
When you assign a clearance to a user, the classification must dominate all classifications at which the user can work. The clearance can be equal to the user's highest work classification. The compartments in the clearance must include all compartments that the user might need.
Arrange the labels in order of increasing sensitivity.
Associate the definitions for each word with an internal format of integers, bit patterns, and logical relationship statements.
A table can be used to keep track of compartment bit assignments. For a completed example, see.
WORDS section under
LABELS to the
INFORMATION LABELS section.
Although Trusted Extensions does not support information labels, the
LABELS: WORDS: section must be identical to the
LABELS: WORDS: section to be a valid encodings file.
Decide which colors should be associated with which labels.
For suggestions and examples, see.
Analyze the label relationships.
On a system that is configured with Trusted Extensions, use the chk_encodings -a command to write a detailed report on the label relationships in your file.
# chk_encodings -a