One of the earliest uses of the term “information warfare” in the context of computer networks was by Thomas Rona in 1976 [
19]. More recently, information warfare has been defined by the United States Air Force as
“any action to deny, exploit, corrupt or destroy the enemy’s information and its functions; protecting ourselves against those actions and exploiting our own military information functions” [
20]. Other authors [
21,
22] agree that information can be both the target of information warfare attacks and the weapon utilised to perform such attacks.
Kuehl [
23] provides another military-oriented definition of information warfare as:
“Information operations conducted during time of crisis or conflict to achieve or promote specific objectives over a specific adversary or adversaries”. Information operations are defined as
“Actions taken to affect adversary information and information systems while defending one’s own information and information systems”. More recent military-oriented definitions include information warfare as
“the process of protecting one’s own sources of battlefield information and, at the same time, seeking to deny, degrade, corrupt, or destroy the enemy’s sources of battlefield information” [
24]. This implies information warfare is a series of offensive and defensive operations. Offensive operations attack information and information systems, while defensive operations defend these targets. This perspective is consistent with the definition given by Denning [
21] who views information warfare as a game played between defenders and attackers involved in a direct competition.
While the work above suggests a strong link between information warfare and the military, other sources [
9,
21,
25,
26,
27] argue that the context of information warfare can be freed from association with its military underpinnings. The focus of information warfare is primarily on the use of information to make decisions, and on how an adversary influences, denies or disrupts the information that is required in the decision-making process [
26]. These processes can occur in non-military contexts including criminal activities and impingement of individual rights.
Technology development has increased significantly compared to when most definitions of information warfare were made. Advances in technology, such as integrated computers, smart mobile phones, smart vehicles, and internet-based industry/home devices, have occurred rapidly in the recent decades. Such technologies have increased risk of becoming targets for information warfare and cyber-attacks. This emphasizes the need to extend the field of information warfare to encompass diverse fields, including in the domains of cyber warfare, cyber-crime, cyber bullying and espionage [
26]. This paper thus considers information warfare in these diverse fields.
While information warfare has been studied widely in the past few decades, there is lack of an agreed definition in the literature [
28]. The remainder of this section thus considers extended definitions for “information” (
Section 2.1), a brief discussion on how related terms in information warfare have been defined (
Section 2.2), the goals of information warfare (
Section 2.3), types of information warfare operations (
Section 2.4) and the recognised domains and actors in information warfare (
Section 2.5). This provides a basis for identifying and classifying information warfare games in
Section 4 which is the primary contribution of this paper.
2.2. Information Warfare Related Terms
The term “information warfare” is often used interchangeably with other terms in the cyber security domain. We consider a number of these terms here and their relationship to information warfare: cyber-space, cyber-attack, cyber-warfare, and cyber-crime.
As with the term “information”, various definitions of cyberspace have been offered by the research community [
29]. One comprehensive definition of cyberspace was offered by Kuehl [
29]. He argued that cyberspace includes more than just computer and digital information aspects. Kuehl concluded that cyberspace includes four important aspects: an operational space, a natural domain, information based and interconnected networks [
28,
29]. To reflect these aspects, Kuehl [
29] defines cyberspace as:
“A global domain within the information environment whose distinctive and unique character is framed by the use of electronics and the electromagnetic spectrum to create, store, modify, exchange and exploit information via interdependent and interconnected networks using information communication technologies.”
The difference between information- and cyber-based assets has also been discussed, including a discussion comparing information security and cyber security [
30]. Unlike information security, cyber security has also been linked to non-information based assets such as human factors. An example is the case where cyber-bullying occurs. It is argued that being bullied in cyberspace does not constitute a loss of confidentiality, integrity, or availability of information. Rather, the victim of such attacks might be the user him/herself.
Taking the definition of cyberspace [
29] into account, Robinson et al. [
28] offered a definition of cyber-attack, as:
“An act in cyber space that could reasonably be expected to cause harm.” Harm in the above definition was viewed in a broad context such as from the perspectives of economic, psychological and physical aspects.
To reach a general definition that can describe any related cyber situation, two major components were considered by Robinson et al. [
28]: (1) the actor, which is the one launching cyber-attacks; and (2) the intent of their attack. An actor can be a state, an individual, a group of terrorists, and so on. The intent, on the other hand, relates to the purpose of the attack performed by the actor. This component plays a key role in the definition. Some examples of common intents [
28] include achieving military objectives (warfare), gaining personal benefit through illegal means (crime), causing psychological distress to another individual (bullying), and influencing a nation’s policies through violence and fear (terrorism [
31,
32]). By considering the two components, the definition extends to any cyber situation. For instance, if the actor is a nation and the intention of launching a cyber-attack is to reach a military objective, than such a situation is considered as cyber warfare. On the other hand, if the actor is an individual who launches a cyber-attack to cause shame, guilt, and depression to other individual, such a situation is likely to be considered as cyber-bullying.
Using the above definition, cyber warfare was defined as:
“The use of cyber attacks with a warfare-like intent” [
28]. This paper adopts the definition of Robinson et al. [
28], as it proposes a methodical approach that can distinguish any cyber events. However, we argue that the intent of cyber-crime may possibly go beyond what was described by Robinson et al. Rather, we adopt a broader view of cyber crime similar to Tekes [
33], who defines cyber-crime as:
“any illegal cyber activity or unlawful computer network action.”By using the above definition, we consider that cyber-crime consists of various activities in the cyberspace that can potentially cause harm and are against the law. Cyber-crime can, therefore, be seen as a broad domain which includes any cyber situations that are unlawful, such as cyber warfare, cyber-bullying, cyber-espionage, and so on. We acknowledge the use of different terms of information warfare and cyber-crimes.
In this paper, we adopt the perspective that information warfare and cyber-crime are two categories that overlap with each other as shown in
Figure 1. Such categories are considered in this paper as a basis to search for and classify game theory literature. In
Section 4.2 we present games that fall in both of these categories, but use information warfare as a general term. The next section thus considers the goals of information warfare.
2.4. Types of Information Warfare Operations
There are numerous definitions for types of information warfare operations, including categorisations that group them according to properties such as whether they are offensive or defensive [
34], the environment they occur in [
25], or the actors in the operation [
9]. This section examines some of these definitions of information warfare operations, and groups them using a selection of common headings. Examples of offensive and defensive information warfare operations are also discussed. These examples provide insight into the core elements of information warfare, and give us a starting point for developing a taxonomy of information warfare games in
Section 4 and
Figure 2.
Schwartau [
9] defines information warfare in a civilian context, describing various attacks against information systems and telecommunications networks. He focuses particularly on offensive information warfare operations. Schwartau [
9] specifies three different types of information warfare attack based on the type of target that is attacked: personal, corporate and global information warfare. Schwartau’s definitions focus primarily on offensive actions, but he recognises that these actions may occur in both civilian and military domains. Other authors specify more types of information warfare attacks, but focus on a particular attach domain such as the military [
20,
23]. Fogleman and Widnall [
20] detail six types of offensive information warfare attacks for the military. A broader taxonomy [
25] divides the information warfare actions by the environment in which they occur. It lists seven types of operations that can be categorised as information warfare. All describe
“conflicts that involve the protection, manipulation, degradation and denial of information”. However, some attacks may overlap multiple categories. More recent work by Ventre [
34] includes a selection of the categories introduced by other researchers, involving both offensive and defensive operations. The following subsections follow Ventre’s taxonomy to some extent, with some additions and name changes to reflect other taxonomies and more recent developments in the information warfare literature.
2.4.1. Offensive Operations
Offensive information warfare operations attempt to control the information environment by paralysing, deteriorating, interrupting, destroying or attempting to deceive information and information systems [
34]. The following types of offensive information warfare have been discussed in the literature.
Command and Control Warfare
Command and control warfare [
25] attacks an opponent’s command and communications infrastructure. It aims to degrade the opponent’s responses to further military action. The destruction of command facilities disrupts military decision-making. Likewise, the destruction of communications infrastructure disrupts the flow of information between decision-makers and the troops implementing those decisions. Command and control warfare has also been categorised simply as ‘physical destruction’ [
20] or ‘physical attacks’ [
34]. These more general terms once again remind us that information warfare has relevance beyond the military context.
Military Deception
Military deception falsely represents the attacker’s capabilities or intentions to the enemy [
20]. More specifically, deception is a series of measures that manipulate, deteriorate or falsify evidence to trigger a reaction that is detrimental to the enemy’s interests [
34]. Deception may involve the employment of physical or electronic means to camouflage one’s own force posture [
24]. Examples of physical deception include the deployment of dummy aircraft on the tarmac of an air base, or broadcasting radio situation reports from “phantom” (dummy) units [
24].
Psychological Warfare
Fogleman and Widnall [
20] define psychological warfare as using information to affect the enemy’s reasoning and thereby their behaviour. Brumley [
7] and Ventre [
34] define psychological warfare in a similar way as the use of information against the human mind. Classical psychological warfare techniques include air dropping propaganda leaflets and using airborne loudspeakers that broadcast demands for surrender [
24].
Libicki [
25] divides psychological warfare into four sub-categories based upon its intended target: counter-will operations, cultural conflict, counter-forces attacks and counter-commander operations. Counter-will operations and cultural conflict are aimed at civilian populations. Counter-will operations counter the opponent’s national will by transmitting a deceptive message to a population. For example, messages may suggest that present and future military attacks are likely to fail. Cultural conflict targets an opponent’s culture. For example, it may attempt to replace their traditions and beliefs with those of the attacker.
In contrast, counter-forces and counter-commander attacks target an opponent’s military troops more specifically. Counter-forces attacks aim to convince troops that fighting is against their best interests. Counter-commander operations intend to confuse and disorientate an opponent’s military commanders, detrimentally affecting their decision-making abilities.
Many aspects of psychological warfare have a long history, independent of the use of ICT. However, ICT can faciliate wider and faster application of psychological warfare techniques. Cyber-bullying is a recent example of the changing nature of psychological cyber-attacks.
Electronic Warfare
Early definitions of electronic warfare describe it as attempts to degrade the physical basis of an opponent’s communications [
25,
35] and attempts to deny the enemy accurate information from the environment [
20]. More recent work describe the goal of electronic warfare as controlling the electromagnetic spectrum [
34]. Brumley [
7] lists three main targets for such electronic warfare attacks: radar receivers, communication systems or communicated messages. Attack types include electronic attacks (jamming), physical assaults or decryption of sensitive messages [
24].
More recently, the focus of electronic warfare has altered to include attacks on services which support physical layer activities [
26]. Whilst the military still maintains separate tactical communication systems, many commercial enterprises have opted for increased integration. One example is the use of the Internet for voice communications. Integrated network systems are considered more vulnerable to attack [
26]. As integration can be applied across wide area, mobile and ad hoc networks, all such networks have potential vulnerabilities.
2.4.2. Defensive Operations
Defensive information warfare operations are carried out to protect and defend friendly information and information systems [
34]. The following types of defensive information warfare have been discussed in the literature.
Operations Security and Security Measures
Information resources are protected from information warfare attacks by using defensive information warfare operations to achieve operational security [
24]. Operations security is a methodology intended to keep an adversary from accessing critical information necessary to correctly evaluate the capabilities and intents of the target. Security programs and security measures are specific steps to conceal an attacker’s military capabilities and intentions from the enemy [
34].
2.4.3. Future Information Warfare Operations
New kinds of information warfare actions can emerge rapidly. Libicki’s [
25] final category of ‘cyberwarfare’ collected a variety of futuristic attacks to emphasise this, some of which have since come to pass. Along with new categories of cyber-crime and cyber-bullying discussed already, an example of an emerging topic in information warfare is the concept of space war [
26]. Uncontrolled or malicious satellites or uncontrolled satellite debris have the potential to create chaos in the space environment. Our dependency on satellite technology heightens the threat posed in this respect. Another aspect of space war more in the domain of information warfare is that of incepted and altered satellite signalling, and misuse of anti-satellite weapons technologies.