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The fault-tolerance property in most cloud storage systems are designed within the scale of a single datacenter. The single datacenter as a whole may be unreachable or crashed due to severe problems, such as broken network links, power supply interruptions, and natural disasters, etc. Therefore, the design of an effective cross-datacenter fault-tolerant storage system is important to protect data security in the cloud. However, building a cross-datacenter fault-tolerant system faces great challenges, such as high latency, low throughput, high costs of bandwidth resources between datacenters. In this paper, we propose a practical cross-datacenter fault-tolerant (CDFT) algorithm in the cloud storage system. Our fault-tolerant algorithm design considers the difficult tradeoffs among fault tolerance, latency, throughput, network and storage costs. We propose the Domain Fault Codes (DFC) and the topology-aware scheduling techniques, which can tolerate the whole datacenter breakdown. We implemented the DFC-CDFT algorithm in a prototype cloud storage system. The experimental results showed that the proposed DFC-CDFT algorithm can effectively recover data blocks from the single datacenter failure while achieves low storage and bandwidth costs. [ABSTRACT FROM AUTHOR]

With the rapid development of Internet of Things technology and the promotion of embedded devices' computation performance, smart devices are probably open to security threats and attacks while connecting with rich and novel Internet. Attracting lots of attention in embedded system security community recently, Trusted Execution Environment (TEE), allows for the execution of arbitrary code within environments completely isolated from the rest of a system. However, existing memory protection methods in a TEE are inadequate. In general, the software-based formal methods are not practical and the hardware-based implementation approaches lack of theoretical proof. To address the memory isolation and protection problems in TEE, in this paper, we propose a practical memory integrity protection method on an ARM-based platform, called MIPE, to defend against security threats including kernel data attacks and direct memory access attacks. MIPE utilizes TrustZone technique to create a isolated execution environment, which can protect the sensitive code and data against attacks. To present the integrity protection strategies, we provide the design of MIPE using B method, which is a practical formal method. We also implement MIPE on the Xilinx Zynq ZC702 evaluation board. The evaluation results show that the automatic proof rate of machines using B method is about 78.32%, and the proposed method is effective and feasible in terms of both load time and overhead. [ABSTRACT FROM AUTHOR]

Semi-interpenetrating polymer networks (Semi-IPNs) based on fluorine-containing polyacrylate and epoxy resin were synthesized by the simultaneous polymerization of fluorine-containing acrylate and epoxy resin. Fourier transform infrared (FTIR) spectrometry and X-ray photoelectron spectroscopy (XPS) analyses proved that the fluorine-containing groups have been introduced into Semi-IPNs successfully. In addition, XPS analysis intuitively showed that the fluorine content of the film-air interface of the interpenetrating fluorine-containing polyacrylate and epoxy resin networks (FPAER-SIPNs) film was much higher than that of the film-glass interface. It is noted that the introduction of fluorine-containing groups significantly improved the hydrophobic property of polymer networks. Moreover, when the fluorine content increased, the contact angle of water on FPAER-SIPNs film was increased obviously and the water uptake was decreased gradually. These results indicated that introducing fluorine-containing groups to SIPNs has potential advantage for improving the surface properties of epoxy resin. [ABSTRACT FROM AUTHOR]