1. In secure communications, a condition under which two or more entities separately have key components that, individually, convey no knowledge of the resultant cryptographic key. [After X9.24]
2. Separation of data or information into two or more parts, each part constantly kept under control of separate authorized individuals or teams so that no one individual or team will know… (Read More →)

On a display device, display space that has been divided into two or more areas, so that each area can display different portions of the same file or portions of different files.
Note 1: The split screen excludes the data lying between the portions of the file or files being displayed and includes the desired data in the two or… (Read More →)

See directional coupler, T-coupler, tee coupler.

The person or organization that requests an evaluation [ITSEC].

A certificate that indicates the restrictions on those documents and transactions that an entity may authorize. [After X9.45]

Radiation emitted when the internal energy of a quantum mechanical system drops from an excited level to a lower level without regard to the simultaneous presence of similar radiation.
Note: Examples of spontaneous emission include radiation from an LED, and radiation from an injection laser below the lasing threshold.

1. (COMSEC) [The] interception, alteration, and retransmission of a cipher signal or data in such a way as to mislead the recipient. [NIS]
2. (AIS) [An] attempt to gain access to an AIS by posing as an authorized user. [NIS]
3. Unauthorized use of legitimate Identification and Authentication (I&A) data, however it was obtained, to mimic a subject different from… (Read More →)

The use of auxiliary storage as buffer storage to reduce processing delays when transferring data between peripheral equipment and the processors of a computer.
Note: The term is derived from the expression "simultaneous peripheral operation on line. "

Irregular scattered patches of relatively dense ionization that develop seasonally within the E region and that reflect and scatter frequencies up to 150 MHz.
Note 1: The sporadic E is a regular daytime occurrence over the equatorial regions and is common in the temperate latitudes in late spring, early summer and, to a lesser degree, in early winter.
Note 2:… (Read More →)

Synonym sporadic E.