Despite the fact that using the services of outsourced data stream servers has been welcomed extremely, still the problem of obtaining assurance about the received results from these untrusted servers in unsecure environment is one of the basic challenges. In this paper, we present a probabilistic model for auditing received results from an outsourced data stream server through unsecure communication channels. In our architecture, the server is considered as a black box and the auditing process is fulfilled by cooperation between the data stream owner and users. Our method imposes an ignorable overhead on the user and needs no change in the structure of the server. The probabilistic modeling of the system proves algorithms convergence and the experimental evaluations show very acceptable results.