Contract Representation for Run-time Monitoring and Enforcement

Converting a conventional contract into an electronic equivalent that can be executed and enforced by computers is a challenging task. The difficulties are caused by the ambiguities that the original humanoriented text is likely to contain. The conversion process involves the conversion of the original text into mathematical notation. This paper discusses how standard conventional contracts can be described by means of Finite State Machines (FSMs). This mathematical description helps eliminate ambiguities from the original text before the contract is coded into a computer program. The paper describes how to map the rights and obligations extracted from the clauses of the contract into the states, transition and output functions, and input and output symbols of a FSM. The FSM representation can be used to guarantee that the clauses stipulated in the contract are observed when the contract is executed. The paper describes the middleware required for the enactment of the contract represented as a FSM.