Defence Signals Directorate is the national authority for Emanation Security (EMSEC). Within DSD, the Information Security Group (ISG) is responsible for the national Emanation Security Program.

All electronic based information systems produce unwanted emanations. These emanations are the electromagnetic radiation emitted from information handling devices. In some cases this can be related to the information being processed and may pose a security risk. Emanation Security involves measures designed to deny unauthorised persons information of value that may be derived from the interception and analysis of compromising emanations.