Starting around 2009, higher bandwidth networks, low-cost commoditized computers and storage, hardware virtualization, large user populations, service-oriented architectures, and autonomic and utility computing together provided the foundation for a dramatic change in the scale at which computation could be provisioned and managed. Popularly, the resulting phenomenon became known as cloud computing. The National Institute of Standards and Technology (NIST), tasked with addressing the phenomenon, defines it in the following way:

“Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.” [1]

In 2011, the U.S. Air Force, through the Air Force Research Laboratory (AFRL) and the Air Force Office of Scientific Research (AFOSR), established the Assured Cloud Computing Center of Excellence (ACC-UCoE) at the University of Illinois at Urbana-Champaign to explore how cloud computing could be used to better support the computing and communication needs of the Air Force. The Center then pursued a broad program of collaborative research and development to address the core technical obstacles to the achievement of assured cloud computing, including ones related to design, formal analysis, runtime configuration, and experimental evaluation of new and modified architectures, algorithms, and techniques. It eventually amassed a range of research contributions that together represent a comprehensive and robust response to the challenges presented by cloud computing. The team recognized that there would be significant value in making a suite of key selected ACC-UCoE findings readily available to the cloud computing community under one cover, pulled together with newly written connective material that explains how the individual research contributions relate to each other and to the big picture of assured cloud computing. Thus, we produced this book, which offers in one volume some of the most important and highly cited research findings of the Assured Cloud Computing Center.

Military computing requirements are complex and wide-ranging. Indeed, rapid technological advances and the advent of computer-based weapon systems have created the need for network-centric military superiority. However, network-centricity is stretched in the context of global networking requirements and the desire to use cloud computing. Furthermore, cloud computing is heavily based on the use of commercial off-the-shelf technology. Outsourcing operations on commercial, public, and hybrid clouds introduces the challenge of ensuring that a computation and its data are secure even as operations are performed remotely over networks over which the military does not have absolute control. Finally, nowadays, military superiority requires agility and mobility. This both increases the benefits of using cloud computing, because of its ubiquitous accessibility, and increases the difficulty of assuring access, availability, security, and robustness.

However, although military requirements are driving major research efforts in this area, the need for assured cloud computing is certainly not limited to the military. Cloud computing has also been widely adopted in industry, and the government has asked its agencies to adopt it as well. Cloud computing offers economic advantages by amortizing the cost of expensive computing infrastructure and resources over many client services. A survivable and distributed cloud-computing-based infrastructure can enable the configuration of any dynamic systems-of-systems that contain both trusted and partially trusted resources (such as data, sensors, networks, and computers) and services sourced from multiple organizations. To assure mission-critical computations and workflows that rely on such dynamically configured systems-of-systems, it is necessary to ensure that a given configuration does not violate any security or reliability requirements. Furthermore, it is necessary to model the trustworthiness of a workflow or computations' completion to gain high assurances.

The focus of this book is on providing solutions to the problems of cloud computing to ensure a robust, dependable computational and data cyberinfrastructure for operations and missions. While the research has been funded by the Air Force, its outcomes are relevant and applicable to cloud computing across all domains, not just to military activities. The Air Force acknowledges the value of this interdomain transfer as exemplified by the Air Force's having patented – with an intended goal of commercialization – some of the cloud computing innovation described in this book.

This material is based on research sponsored by the Air Force Research Laboratory (AFRL) and the Air Force Office of Scientific Research (AFOSR) under agreement number FA8750-11-2-0084, and we would like to thank AFRL and AFOSR for their financial support, collaboration, and guidance.¹ The U.S. Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon. The work described in this book was also partially supported by the Boeing Company and by other sources acknowledged in individual chapters.

The editors would like to acknowledge the contributions of the following individuals (in alphabetical order): Cristina L. Abad, Gul Agha, Masooda N. Bashir, Rakesh B. Bobba, Chris X. Cai, Roy H. Campbell, Tej Chajed, Brian Cho, Domenico Cotroneo, Fei Deng, Carlo Di Giulio, Peter Dinges, Zachary J. Estrada, Jatin Ganhotra, Mainak Ghosh, Jon Grov, Indranil Gupta, Gopalakrishna Holla, Jingwei Huang, Jun Ho Huh, Ravishankar K. Iyer, Zbigniew Kalbarczyk, Charles A. Kamhoua, Manoj Kumar, Kevin A. Kwiat, Luke Kwiat, Luke M. Leslie, Tianwei Li, Philbert Lin, Si Liu, Yi Lu, Andrew Martin, José Meseguer, Priyesh Narayanan, Sivabalan Narayanan, Son Nguyen, David M. Nicol, Shadi A. Noghabi, Peter Csaba Ölveczky, Antonio Pecchia, Boyang Peng, Cuong Pham, Mayank Pundir, Muntasir Rahman, Nathan Roberts, Aashish Sharma, Reza Shiftehfar, Yosub Shin, Stephen Skeirik, Read Sprabery, Sriram Subramanian, Jian Tang, Gary Wang, Wenting Wang, Le Xu, Lok Yan, Mindi Yuan, and Mammad Zadeh. We would also like to thank Todd Cushman, Robert Herklotz, Tristan Nguyen, Laurent Njilla, Andrew Noga, James Perretta, Anna Weeks, and Stanley Wenndt. Finally, we would like to thank and acknowledge Jenny Applequist, who helped edit and collect the text into its final form, as well as Mary Hatcher, Vishnu Narayanan, Victoria Bradshaw, and Melissa Yanuzzi of Wiley and Vinod Pandita of Thomson Digital for their kind assistance in guiding this book through the publication process.