Attack trees are conceptual diagrams that show how an entity or target can be attacked. Attack trees have been used in many different applications. In the field of information technology, they have been used to describe threats in computer systems and alternative attacks that would make these threats real. However, the use of attack trees is not limited to the analysis of information systems. Attack trees are also frequently used for threat analysis in anti-tamper electronic systems (eg avionic systems in military aircraft) in the defense and aerospace field. Attack trees are also increasingly used in computer control systems (especially for power distribution lines). Attack trees have also been used to understand attacks on physical systems.