Distributed Computing Column 39: Byzantine Generals: The Next Generation

The relevance of Byzantine fault tolerance in the context of cloud computing has been questioned[3]. While arguments against Byzantine fault tolerance seemingly makes sense in the context of a singlecloud, i.e., a large-scale cloud infrastructure that resides under control of a single, typically commercialprovider, these arguments are less obvious in a broader context of the Intercloud, i.e., a cloud of multiple,independent clouds.In this paper, we start from commonly acknowledged issues that impede the adoption of Byzantinefault tolerance within a single cloud, and argue that many of these issues fade when Byzantine faulttolerance in the Intercloud is considered.