Labels' Components

Both labels and clearance labels are made up of a single classification and zero or more compartment words. The human-readable format of labels is shown in the following table.

Table 1-1 Components of a Label

Classification	Compartments
name	[word1, word2, ..., wordN]

The security administrator creates all the label components by assigning names and numeric values to classifications and assigning compartment words to bits in the label_encodings(4) file. Along with a classification field of 15 bits, each label and clearance label has a 256 bit field available for compartments, as shown in Table 1-2. Each compartment word has one or more compartment bits assigned. The same compartment bit may be assigned to more than one word.

Table 1-2 Bits and Values for Classification and Compartment Components

Classification	Compartments
15 bits  32,767 possible values  256 values limit enforced	256 bits  possible compartment and bit combinations: 10 to the 70 power

The classification portion of a label indicates a relative level of protection. When a label is assigned to an object, the label's classification indicates the sensitivity of the information contained in the object. When a clearance label is assigned to a user, the classification portion of the clearance label indicates the user's level of trust.

The use of one or more optional compartment words in a label can help to group individuals with a common area of interest and to further identify how information should be handled. A compartment word can be used to represent what ever kind of grouping you desire, such as a work group, a department, a division, or a geographical area.

For example, a classification of NEED TO KNOW in a label can be restricted by the presence of one or more compartment words defined with department names, such as ENGINEERING or HUMAN RELATIONS or LEGAL. A file with NEED TO KNOW LEGAL would be available only to individuals who have the NEED TO KNOW classification and the LEGAL compartment in their clearances.