CIPHER

1. [A] cryptographic system in which units of plain text are substituted according to a predetermined key . [ NIS ] Note: A cipher is any cryptographic system in which arbitrary symbols, or groups of symbols, represent units of plain text of regular length, usually single letters, or in which units of plain text are rearranged, or both, in accordance with certain predetermined rules. 2. The result of using a cipher. Note: An example of a cipher is an enciphered message or text.