The last two chapters discussed how intelligence influences the main world of action. This one deals with its effects on another, specialized area: governments’ own secrecy and information control. They want accurate information and good forecasts about other states; but they also want to control what these others are able to find out about them, so they erect information defences. Counterespionage and counterintelligence have already been noted in this defensive role. This chapter describes more fully how offensive intelligence is connected with defensive information protection.

The terminology is confusing. The protection of information is information security, usually shortened in this context to ‘security’. It should not be confused with ‘security’ as national security and its subdivisions into external and internal security; or with security intelligence (already discussed) on threats to internal security. Information security supports national security but is not limited to this area of government activity (see figure 11).

Governments want ‘security’ (information security) over a wide range of matters. Thus the country's internal security includes information security measures to frustrate foreign espionage, and external security includes similar measures to protect military and diplomatic communications against foreign interception and exploitation. But some things outside any reasonable definition of the national security area also need information security protection, for example sensitive economic and financial information or even confidential information about individuals.