Trust in Cloud Infrastructure and Security in Sensor Cloud Computing

In this paper, we outline research issues in cloud computing with respect to trustworthiness of the cloud infrastructure, as well as security measures needed in sensor cloud paradigm. The objective is to develop the missionoriented security risk management framework to evaluate the cloud infrastructure for any given application as well as design security approaches which can be used for securing the sensor cloud infrastructure. 1. Risk Evaluation in Cloud Computing Security concerns are the most prominent reasons that discourage organizations to adopt to cloud services [1]. Therefore, while considering the cloud adoption, cloud consumers need a way to measure the security capability of the cloud-based resources. Unfortunately, cloud environment is not homogeneous as each cloud has its own infrastructure, platforms, safeguards, and other varied characteristics. Thus, it is not an easy task for the cloud consumers to demand a technological compatibility from federated cloud. Similarly, it is a difficult task for a cloud provider to find another provider who deploys the security measures compatible to it. In fact, cloud changes the dynamic of how to address the threats on an environment where the underlying architecture is completely transparent to the consumer and, hence, considering the “presence” and “absence” of security mechanism in isolation is no longer sufficient. Materializing security risk analysis requires evaluator to consider the system properties that contribute to the quality of security assurance. The primary goal is to develop a way to gauge the trustworthiness of individual cloud elements or aggregate cloud resources and to suggest the best mitigation strategy. Understanding the reliance on vender’s security measures is fundamental to the formulation of coherent strategy regarding to cloud security. Cloud changes the dynamic of how to address the threats and, hence, make many client companies reluctant to adopt the technology. We outline this research in two directions, namely, off-line risk management and on-line trust evaluation. The goal of the off-line scheme is to understand risks and reliance on vender’s security capability so as to make the best vender selection and cloud migration strategy. Most traditional security best practices rely heavily on standards compliance. When adapting to the offpremised cloud-based infrastructure, it is not enough to just consider the “presence” and “absence” of security best-practices in isolation. Materializing security risk analysis requires evaluator to consider the system properties that contribute to the quality of security assurance. We envision having the framework begin as early as the system engineering process. As oppose to a vender-specific approach, the underlined framework should built around the mission where the assessment starts from the requirement analysis process to understand security concerns and dependencies between mission, tasks, assets and applications before extending toward cloud provider’s infrastructure. Ideally, such an approach should be scalable and applicable across a broad range of cloud elements. The proposed approach should connect the project assessment, risk assessment, vender assessment, and finally the trade-off analysis. The primary objective is to develop the missionoriented security risk management framework which takes an input the abstraction of the system ontology and outputs the off-premise risk assessment model. This output will help system engineer understand risks and reliance on vender’s security capability so as to make the best vender selection and cloud migration strategy. Understanding the reliance on vender’s security measures is fundamental to the formulation of coherent strategy regarding to cloud security. The offpremise risk management shall be included early in the preliminary project design prior to vender selection. The path toward our mission objective consists of three tasks. We outline them as following. 1.1 To Develop an Assessment Model that Incorporates Threats and Impacts We wish to build a data model of the organization in terms of “security objectives”, “Threats”, “Tasks”, “Assets” and “Application Vulnerabilities”. If some of the assets or applications are migrated to the cloud then this data model can be used to evaluate the impact of threats. The model does not only identify “threats” but also “where” they are present and the implications of their impacts to an underline task or application. Besides, an evaluator may have interest to prioritize the impact of threats. The impact can be qualitatively scaled or can be measured by attack surface [2]. 1.2 To Develop a Vender Assessment Model in terms of Threats, Impacts, and Venders Security Mechanism (Detective, Preventive, and Reactive) We wish to explore the vender assessment model based on standard compliance and public artifacts. Standard compliance has been well accepted by researches and industries in that, it can positively reduce security concerns which in turn reduce the demand for legislation and reduce the risk on service outsourcing [3]. The question to explore is that, given a standard compliant, what is the security coverage the cloud provider can guarantee? Similarly, given a set of security coverage how can we measure the security satisfaction on client’s assertions? Intuitively, the 128 bits cryptography is theoretically stronger than 64 bits key, however, it also depends on the communication and key management protocol as well. 1.3 To Develop a cost-benefit Tradeoff for Optimal Cloud Adoption Strategy Vender assessment is not the end of the cloud adoption. Rather, we are expected to face a more challenging problem of the cost-benefit trade-off between a complete cloud adoption, partial cloud adoption, and non-cloud adoption. Assessing the choices of implementation triggers the need for an assessment of cloud adoption plan evaluation. In particular, an evaluator is expected to identify the share of responsibility, and estimate and assess the providers service cost and the security control cost paid on the client’s share of responsibility. 2. Security in Sensor Cloud Sensor cloud computing is a heterogeneous computing environment where there are potentially tens of thousands of deployed sensors geographically spread apart. The sensor cloud provisions the use of physical sensors through the virtualization of sensing services. The virtualization significantly expands the boundary of service capability to facilitate a variety of missions [5, 6, 7]. Sensor cloud is particularly attractive as it can change the computation paradigm of wireless sensor networks in near future. As reported in [4,8], sensor clouds have various applications including environment monitoring, enterprise computing, scientific simulation, and social networking. Naming some efforts in sensor cloud directions are Open Geospatial Consortium’s (OGC) Sensor Web, Microsoft SensorMap, and, Asia-Pacific Environmental Sensor Grid (APESG). In sensor cloud computing network, users do not need to own sensors; they can simply rent different sensor-based services. This significantly reduces the cost of ownership thus making the usage of large scale sensor networks become affordable. One physical sensor can be mapped to multiple virtual sensors and vise-versa. The nature of sensor cloud thus enables resource sharing and allows virtual sensors to scale up or down as and when needed. Also, the sensor cloud abstracts different platforms of the physical devices hence giving the impression of a homogeneous network, thus greatly benefiting users from this infrastructure transparency. Finally, a variety of multi-sensing activities for multiple missions can be simultaneously performed via the cloud which also enhances the usability of the devices and networks. 2.1 Security Challenges in Sensor Cloud