Encodings File Syntax

The label_encodings file contains a VERSION specification and seven mandatory sections:

• CLASSIFICATIONS

• INFORMATION LABELS

• SENSITIVITY LABELS

• CLEARANCES

• CHANNELS

• PRINTER BANNERS

• ACCREDITATION RANGE

The sections must appear in that order. An optional LOCAL DEFINITIONS section can follow.

In the following table, mandatory keyword means only that the keyword must be present. Not all keywords must have definitions. The notes for each section indicate what must be defined and what is optional.

Table 3-1 label_encodings Keywords

For all the required sections, the keywords in the preceding table must be present, but not all of the sections must have definitions. For example, a label_encodings file with only CLASSIFICATIONS and ACCREDITATION RANGE definitions is valid.

Word Order Requirements

The order in which words are configured for sensitivity labels and clearances is not enforced. However, the order is important when you set up relationships between words. By convention, the WORDS in the SENSITIVITY LABELS section are arranged in increasing order of sensitivity.

For the effect of word order, see Specifying Channels. Detailed information is provided in Compartmented Mode Workstation Labeling: Encodings Format: Defense Intelligence Agency document [DDS-2600-6216-93].

If a compartment word is defined for one type of label (by assigning the compartment word to one or more bits) in the label_encodings file, then the same bits must be assigned to a word in the definition of the other types of labels. While all types of labels use the same classification names, the words that are used for each type of label can be different. The words can be different even when they are encoded with the same bits and literally refer to the same thing. Clearance labels can allow combinations of words that have been disallowed in the definitions for sensitivity label words.

Classification Name Syntax

The classification is the hierarchical portion of a label. Each label has one and only one classification. A site can define up to 255 classifications. An integer value from 1 to 255 can be assigned to a classification in the label_encodings file. The value 0 is reserved for the ADMIN_LOW administrative label. The value 32,767 is reserved for the ADMIN_HIGH administrative label. For an illustration of a CIPSO label, see Figure 1-2.

Classifications are defined once for clearances and once for sensitivity labels in the CLASSIFICATIONS section of the label_encodings file.

A classification with a higher value dominates a classification with a lower value. The following table shows two sets of label names that are assigned the same values in different encodings files. The left column shows sample sensitivity labels from the label_encodings.example file. The middle column shows labels from the label_encodings.gfi.multi file. A label with the Registered or Top Secret classification, with a value of 6, dominates the labels that are listed in its column.

Keywords for Classifications

The following list describes the keywords that can be defined for classifications. For examples of initial compartment definitions, see Default and Inverse Words.

name=

Mandatory. Cannot contain (/), (,) or (;). All other alphanumeric characters and white space are allowed. Users can specify the name, the sname or the aname when specifying labels.

sname=

Mandatory in classifications only. The short name appears in sensitivity labels.

aname=

Optional. The alternative name that can be specified by users when a classification is needed.

value=

Mandatory. The values that you assign to represent the hierarchy among the classifications. Leave gaps for later expansion. 0 is reserved for ADMIN_LOW. Values can start at 1 and go to 255.

initial compartments=

Optional. Specify bit numbers for any default compartment words. Default compartment words initially appear in any label that has the associated classification.

Advanced: Specify bit numbers for any inverse words. The minimum classification must not have initial compartments. For a description of inverse words, see Default and Inverse Words.

initial markings=

Obsolete. Do not define.

The following example shows the beginning of the label_encodings.multi file.

Example 3-1 Classifications With Initial Compartments in label_encodings.multi File

VERSION= Trusted Extensions Multi-Label GFI Distributed Demo Version 

*
*    WARNING:  If CIPSO Tag Type 1 network labels are to be used:
*
*        a) All CLASSIFICATIONS values must be less than or equal to 255.
*        b) All COMPARTMENTS bits must be less than or equal to 239.
*

CLASSIFICATIONS:

*
name= UNCLASSIFIED;  sname= U;  value= 1;
name= CONFIDENTIAL;  sname= C;  value= 4; initial compartments= 4-5 190-239;
name= SECRET;        sname= S;  value= 5; initial compartments= 4-5 190-239;
name= TOP SECRET;    sname= TS; value= 6; initial compartments= 4-5 190-239;

Each classification has the mandatory name, sname, and value fields. The CONFIDENTIAL, SECRET, and TOP SECRET classifications have initial compartments. The lowest classification, UNCLASSIFIED, has no initial compartments.

The initial compartment bit assignments of 4-5 and 190-239 signify that bits 4, 5, and 190 through 239 are turned on. These bits are set to 1 in a label with this classification.

Some of the initial compartments are later used to define default and inverse words. Some initial compartments are reserved for possible later definitions of inverse words.

The following example shows a set of classifications that has no initial compartments.

Example 3-2 Classifications With No Initial Compartments in label_encodings.example File

CLASSIFICATIONS:

name= PUBLIC; sname= PUBLIC; value= 1;
name= INTERNAL_USE_ONLY; sname= INTERNAL; aname= INTERNAL; value= 4;
name= NEED_TO_KNOW; sname= NEED_TO_KNOW; aname= NEED_TO_KNOW; value= 5;
name= REGISTERED; sname= REGISTERED; aname= REGISTERED; value= 6;

Default and Inverse Words

When a bit is defined as an initial compartment, the bit is set to 1 in every label that contains the classification. Any bit that is specified for an initial compartment can be defined later in the label_encodings file as a default compartment word (default word) or an inverse compartment word (inverse word).

• A default word is a word that appears in any label that contains the classification.

• An inverse word is a word that appears in a label that has the associated classification when another word that you define with the inverse compartment's bit is not present.

Example 3-3 Assigning Initial Compartments

In this example, the PUBLIC classification is assigned no initial compartments, while the WEB COMPANY classification is assigned initial compartments 4 and 5. A label that includes the PUBLIC classification has no default compartments. A label that includes the WEB COMPANY classification always has compartment bits 4 and 5 turned on.

name= PUBLIC;  sname= P;  value= 1;
name= WEB COMPANY;  sname= WEBCO;  value= 4; initial compartments= 4-5

The following shows how these initial compartment bits can be assigned to words by defining default and inverse words under SENSITIVITY LABELS.

SENSITIVITY LABELS:

WORDS:

name= DIVISION ONLY;  sname= DO;       minclass= WEB COMPANY; compartments= 4-5;
name= WEBC AMERICA;   sname= WEBCA;    minclass= WEB COMPANY; compartments= ~4;
name= WEBC WORLD;     sname= WEBCW;    minclass= WEB COMPANY; compartments= ~5;

In the preceding WORDS example, compartment bits 4 and 5 are assigned to the word DIVISION ONLY. Each compartment bit is also associated with an inverse word. The sensitivity label name WEBC AMERICA is assigned to the inverse compartment bit ~4. The sensitivity label name WEBC WORLD is assigned to the inverse compartment bit ~5. These assignments have the following results:

• A sensitivity label with the WEB COMPANY classification initially includes the word DIVISION ONLY. The label's binary representation has the compartment bits 4 and 5 turned on.

• A sensitivity label with the PUBLIC classification always has compartment bits 4 and 5 turned off. The inverse words WEBC AMERICA and WEBC WORLD are included in the label.

  Because a minclass of IUO is specified for the inverse words, WEBC AMERICA and WEBC WORLD are not displayed in the PUBLIC sensitivity label. The presence of these two inverse words is understood.

Compartment Words

Compartments are optional words that can be defined to appear in labels. Compartments are called categories in some other trusted systems. Compartments are used to indicate the special handling procedures to be used for the information whose label contains the compartment and the general class of people who might have access to the information.

Compartment words are assigned to non-hierarchical bits. However, hierarchies can be established between compartment words. These hierarchies are based on rules for including bits from one compartment word in the bits that are defined for another compartment word.

Compartment words are optionally defined in the WORDS subsection for each label type. Each compartment word is assigned to one or more bits.

While all types of labels use the same classifications, the words that are used for each type of label can be different. The words can be different even when they are encoded with the same bits and literally refer to the same thing.

The following example shows the WEB COMPANY compartment word. The word is specified with a short name (sname) of WEBCO and compartment bits 40-50.

WORDS:

name= WEB COMPANY; sname= WEBCO; compartments= 40-50;

Along with its classification field, each label has a 256–bit compartment field, of which 239 are available for CIPSO labels. Each bit is assignable in zero or more compartment words. Each word can have one or more compartment bits assigned. Out of the 239 available bits, many compartment words can be created. For an example, see the compartments planner in Table 6-3.

The classification, compartments, and combination requirements affect the accreditation range. The ACCREDITATION RANGE for each classification setting must be one of the following strings:

• only valid compartment combinations;

• all compartment combinations valid;

• all compartment combinations valid except;

Hierarchical Compartment Words

Hierarchical compartments can be used to differentiate between documents that are available to everyone in a larger group, and documents that are available to subgroups only.

Example 3-4 Using Bit Combinations to Establish Hierarchies

By defining a word that uses one bit and a second word that uses that same bit along with a second bit, you define a hierarchical relationship between the two words. The more general compartment word must be defined below the word that is more specific. For example, by defining a word that uses bit number 1 and another word that uses bits number 1 and 2, you give the two words a hierarchical relationship.

In this example, a Sales compartment is defined with two subcompartments, Direct_Sales, and Indirect_Sales. A single classification that is named WebCo is previously defined.

name= Direct_Sales;   compartments= 1, 2
name= Indirect_Sales;   compartments= 1, 3
name= Sales;   compartments= 1

This definition allows the WebCo company to differentiate between documents that can be accessed by anyone in the entire sales department, documents that can be accessed only by members of the direct sales department, and documents that can be accessed only by members of the indirect sales department.

The assignments and effects are as follows:

• The security administrator assigns the WebCo Direct_Sales clearance to employees in the direct sales department. The WebCo Indirect_Sales clearance is assigned to employees in the indirect sales department.

• Documents that are created by an employee who is working at the WebCo Direct_Sales label are labeled with the label that is only accessible to employees in the direct sales department.

• Anyone in the indirect or direct sales departments can work at the WebCo Sales label because the compartment word Sales is below both the Direct_Sales and Indirect_Sales words. Creating documents at the WebCo Sales label makes the documents available to everyone in the sales department.

Example 3-5 Using REQUIRED COMBINATIONS to Establish Hierarchies

If two words are specified together in the REQUIRED COMBINATIONS section, the second label is added to the label whenever the first word is used.

In this example, the definitions of the Direct_Sales, Indirect_Sales, and Sales compartments serve essentially the same purpose as in Example 3-4. The difference is that the Direct_Sales word will always have the Sales word with it.

name= Direct_Sales;   compartments= 2
name= Indirect_Sales;   compartments= 3
name= Sales;   compartments= 1

REQUIRED COMBINATIONS:

Direct_Sales            Sales
Indirect_Sales          Sales