The Initial Markings= Keyword

The initial markings= keyword is optional, and is used to specify the initial, or default values of marking bits in an information label containing the associated classification. The initial markings specification consists of a list of those marking bits that should be 1 in such a label, with unspecified bits being 0. If no initial markings= keyword is specified for a particular classification, all initial marking bits for that classification are taken to be 0.

There are two reasons why the initial markings associated with a classification would need to be non-zero. The first is the case where it is desired that all information labels on the system containing that classification must have some word (e.g., NOFORN) present, in which case the 1 marking bits associated with the word would be specified as 1 in the initial marking bits. (The association between words and their marking bits is made by the markings= keyword in the INFORMATION LABELS: section of the encodings.) Such a word is called a default word and the marking bits associated with the word are called default bits.

The second is the case where the initial markings specify which marking bits are used inversely. (A prefix can also be used to specify compartment bits to be used inversely. Inverse bits specified by prefix words are called special inverse bits. See Defining Prefixes And Suffixes in Chapter 4, Information Label Encodings, and Using Prefixes to Specify Special Inverse Compartment and Marking Bits in Chapter 7, General Considerations for Specifying Encodings.) An inverse marking bit is a bit whose 0 value is associated with the presence of a word and whose value is 1 unless the word is present in the label. Inverse marking bits are associated with inverse words, whose addition to a label does not increase the sensitivity of the label, but instead either decreases or otherwise changes the sensitivity of the label, (i.e., changes at least one bit in the internal form of the label from 1 to 0). Normal (non-inverse) marking bits are associated with words whose addition to a label increases the sensitivity of the label by changing one or more bits from 0 to 1.)

All initial marking bits that are not inverse bits are considered default bits. All default bits must have default words associated. All words that have associated default bits can have only default bits associated.

The specification of marking bits starts with the first non-blank character following the blank after the initial markings= keyword, and continues up to the next semicolon or the end of the line. The specification consists of one or more blank-separated subspecifications which consist of either 1) a decimal integer specification of a bit position, numbering bits from the left starting at 0, or 2) a range of such bit positions specified as two decimal integers with a “-” in between. The start of a range must be lower than the end of a range. The maximum bit position allowed is 127, for a total of 128 bits. Table 3-2 shows examples of initial markings specifications.

Table 3-2 Initial Markings Specifications

If initial markings= is specified more than once for the same classification, the marking bits indicated in each specification are taken together to form one composite initial markings specification. Thus, the two specifications:

initial markings= 11; initial markings= 17;

are equivalent to the single specification:

initial markings= 11 17;

However, for the sake of clarity, at most one initial markings= keyword should be specified per classification.