Abstract
Cloud computing is a forthcoming revolution in information technology industry because of its performance, accessibility and, low cost. It is appropriate to maximize the capacity or step up capabilities vigorously without investing in new infrastructure, nurturing new personnel or licensing new software. The federated cloud, which is the combination of more than one cloud, is the next logical step after hybrid cloud and there are many indicators that are showing more requirements for such a model. Security is the challenging issue in all cloud infrastructures such as single cloud and federated cloud. And, it is significant in distributed systems which have highly fault tolerant. One of the algorithms for this issue is Byzantine Fault Tolerant. This paper introduces a new method, that optimizes the Byzantine Fault Tolerant and decrease the latency, and detecting the number of faults.