Cloud computing provides economic advantages from shared resources, but security is a major risk for remote operations and a major barrier to the approach, with challenges for both hosts and the network. NEBULA is a potential future Internet architecture providing trustworthy networking for the emerging cloud computing model of always-available network services. NEBULA addresses many network security issues, including data availability with a new core architecture (NCore) based on redundant connections to and between NEBULA core routers, accountability and trust with a new policy-driven data plane (NDP), and extensibility with a new control plane (NVENT) that supports network virtualization, enabling results from other future Internet architectures to be incorporated in NEBULA. NEBULA?s data plane uses cryptographic tokens as demonstrable proofs that a path was both authorized and followed. The NEBULA control plane provides one or more authorized paths to NEBULA edge nodes; multiple paths provide reliability and load-balancing. The NEBULA core uses redundant high-speed paths between data centers and core routers, as well as fault-tolerant router software, for always-on core networking. The NEBULA architecture removes network (in) security as a prohibitive factor that would otherwise prevent the realization of many cloud computing applications, such as electronic health records and data from medical sensors. NEBULA will produce a working system that is deployable on core routers and is viable from both an economic and a regulatory perspective.