Abstract. The event-condition-action (ECA) paradigm holds enormous potential in pervasive computing environments. However, the problem of reliable delivery of event data, generated by low capability sensor devices, to more capable processing points and vice versa, needs to be addressed for the success of the ECA paradigm in this environment. The problem becomes interesting because strong cryptographic techniques for achieving integrity impose unacceptable overhead in many pervasive computing environments. We address this problem by sending the data over the path from the sensor node to the processing point that provides the best opportunity of reliable delivery among competing paths. This allows using much weaker cryptographic techniques for achieving security. The problem is modeled as a problem of determining the most reliable path – similar to routing problems in networks. We propose a trust-based metric for measuring reliability of paths. The higher the trust value of a path the ...