The principal difference between an attack tree and a fault tree lies in how you enter and traverse each:
- Fault trees are not based on intelligently planned attacks in which leaves of the tree are entered according to the will of an intelligent entity (though a decision may drive the device or system into a state whereby the leaf is entered)
- Fault trees are traversed based on stochastic processes (failure/fault rates) from each leaf through the dependent, intermediate nodes
- Each fault tree leaf is completely independent (faults occur randomly and independently of each other) of all other leaves of the tree
A fault tree can account for the rate at which an aircraft's braking system may fail naturally, ...
