National intelligence programs, and, by extension, the overall defenses of nations, are vulnerable to attack. It is the role of intelligence cycle security to protect the process embodied in the intelligence cycle, and that which it defends. A number of disciplines go into protecting the intelligence cycle. One of the challenges is there are a wide range of potential threats, so threat assessment, if complete, is a complex task. Governments try to protect three things: Their intelligence personnel Their intelligence facilities and resources Their intelligence operations Defending the overall intelligence program, at a minimum, means taking actions to counter the major disciplines of intelligence collection techniques: Human Intelligence (HUMINT) Signals Intelligence (SIGINT) Imagery Intelligence (IMINT) Measurement and Signature Intelligence (MASINT) Technical Intelligence (TECHINT) Open Source Intelligence (OSINT) To these are added at least one complementary discipline, counterintelligence (CI) which, besides defending the six above, can itself produce positive intelligence. Much, but not all, of what it produces is from special cases of HUMINT. Also complementing intelligence collection are additional protective disciplines, which are unlikely to produce intelligence: Physical security (PHYSEC) Personnel security (PERSEC) Communications security (COMSEC) Information system security (INFOSEC) Security classification Operations security (OPSEC) These disciplines, along with CI, form intelligence cycle security, which, in turn, is part of intelligence cycle management. Disciplines involved in "positive security", or measures by which one's own society collects information on its actual or potential security, complement security. For example, when communications intelligence identifies a particular radio transmitter as one used only by a particular country, detecting that transmitter inside one's own country suggests the presence of a spy that counterintelligence should target. CI refers to efforts made by intelligence organizations to prevent hostile or enemy intelligence organizations from successfully gathering and collecting intelligence against them. Frank Wisner, a well-known CIA operations executive said of the autobiography of Director of Central Intelligence Allen W. Dulles, that Dulles "disposes of the popular misconception that counterintelligence is essentially a negative and responsive activity, that it moves only or chiefly in reaction to situations thrust upon it and in counter to initiatives mounted by the opposition" Rather, he sees that can be most effective, both in information gathering and protecting friendly intelligence services, when it creatively but vigorously attacks the "structure and personnel of hostile intelligence services. In 1991 and 1995 US Army manuals dealing with counterintelligence, CI had a broader scope against the then-major intelligence