Strategic Re ection ?

The Maude system incorporates reeective capabilities that enable quite sophisticated strategies to be expressed very conveniently. Maude's strategy languages have been used to control the execution of large and small rewriting systems, in several areas of application. Strategies have been used to encode winning strategies for games, and can also be used for more serious purposes, such as theorem-proving strategies, and strategies taking the place of model checkers or nite-state exploration tools in the analysis of nite-state systems. In particular, nite-or innnite-state systems, such as secure communication protocols, can be speciied in rewriting logic and can be subjected to formal analysis through strategies at the metalevel. Communication protocols can be speciied as concurrent object-oriented systems communicating through message passing, and can be executed as Maude programs. Nondetermin-istic behavior such as the order of messages arrival in such protocols can be controlled via strategies at the metalevel so that all possible behaviors of a system are explored. Previously-known and previously-unknown attacks or aws in cryptographic and multicast protocols have been discovered through the use of Maude's strategy mechanisms. In this paper several examples of the successful use of this and other kinds of strategies are pointed out.