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The issue of security in fog has several challenges and one of which is to create a secure channel that connects fog layer to the end devices. Therefore, efficient and secure key distribution is very important to create this channel. One solution is key pre-distribute that the keys generation and distribution between nodes are before the network establishment. This article presents an algorithm for key pre-distribution in fog networks that focuses on the relationship between end devices and the fog layer. The proposed scheme is a hybrid scheme that uses the K-MEANS algorithm for nodes hierarchical clustering. Then the residual design is used to generate the key chain and BIBD design is used for key pre-distribution in headers. The proposed method is completely independent of the mobility model of and its communication and computation overheads are of the order of O(q). Also, the network connectivity is above 0.8 and close to the BIBD design, which is a fully connected KPS, and the probability of capturing the entire network in case of capturing the nodes is almost equal to 0. In the proposed method for a network with size N, the size of the key chain is N 4. [ABSTRACT FROM AUTHOR]

The ability of data owner in secure and efficient arbitrary data sharing with others is of great importance in the outsourced encrypted data on the cloud. To protect data confidentiality, data owner encrypts his files before storing information on the cloud. Data sharing schemes are used to share encrypted files with others. Guo et al.'s data sharing scheme in dynamic cloud storage is evaluated in this paper. We investigate its vulnerability against DoS and impersonation attacks. In this scheme, anyone can forge the authentication key and access any arbitrary set of files stored on the cloud. We present a new scheme to overcome the weaknesses. Moreover, we evaluate the security and efficiency of our scheme comparing to some related ones. The results indicate that the proposed scheme is suitable for data sharing in dynamic cloud storage. [ABSTRACT FROM AUTHOR]

The need for cyber resilience is increasingly important in our technology-dependent society where computing devices and data have been, and will continue to be, the target of cyber-attackers, particularly advanced persistent threat (APT) and nation-state/sponsored actors. APT and nation-state/sponsored actors tend to be more sophisticated, having access to significantly more resources and time to facilitate their attacks, which in most cases are not financially driven (unlike typical cyber-criminals). For example, such threat actors often utilize a broad range of attack vectors, cyber and/or physical, and constantly evolve their attack tactics. Thus, having up-to-date and detailed information of APT’s tactics, techniques, and procedures (TTPs) facilitates the design of effective defense strategies as the focus of this paper. Specifically, we posit the importance of taxonomies in categorizing cyber-attacks. Note, however, that existing information about APT attack campaigns is fragmented across practitioner, government (including intelligence/classified), and academic publications, and existing taxonomies generally have a narrow scope (e.g., to a limited number of APT campaigns). Therefore, in this paper, we leverage the Cyber Kill Chain (CKC) model to “decompose” any complex attack and identify the relevant characteristics of such attacks. We then comprehensively analyze more than 40 APT campaigns disclosed before 2018 to build our taxonomy. Such taxonomy can facilitate incident response and cyber threat hunting by aiding in understanding of the potential attacks to organizations as well as which attacks may surface. In addition, the taxonomy can allow national security and intelligence agencies and businesses to share their analysis of ongoing, sensitive APT campaigns without the need to disclose detailed information about the campaigns. It can also notify future security policies and mitigation strategy formulation. [ABSTRACT FROM AUTHOR]

Wireless sensor networks have been established for a wide range of applications in adversarial environments, which makes secure communication between sensor nodes a challenging issue. To achieve high level of security, each pair of nodes must share a secret key in order to communicate with each other. Because of the random deployment of sensors, a set of keys must be pre-distributed, so that each sensor node is assigned a set of keys from a key pool before the deployment. The keys stored in each node must be carefully selected to increase the probability of key share between two neighboring nodes. In this paper, we consider a hybrid key pre-distribution scheme based on the balanced incomplete block design. We present a new approach for choosing key pool in the hybrid symmetric design that improves the connectivity and scalability of the network. We also introduce an extension to the proposed approach to detract memory usage and improve resilience. Experimental results verify the performance and applicability of our approach. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We report the results of a high-performance all-solid- state broad-band frequency multiplier chain at 1500 GHz, which uses four cascaded planar Schottky-barrier varactor doublers. The multipliers are driven by monolithic-microwave integrated-circuit- based high electron-mobility transistor power amplifiers around 95 GHz with 100-150 mW of pump power. The design incorporates balanced doublers utilizing novel substrateless and membrane device fabrication technologies, achieving low-loss broad-band multipliers working in the terahertz range. For a drive power of approximately 100 mW in the 88-99-GHz range, the doublers achieved room-temperature peak efficiencies of approximately 30% at the 190-GHz stage, 20% at 375 GHz, 9% at 750 GHz, and 4% at the 1500-Gift stage. When the chain was cooled to 120 K, approximately 40 μW of peak output power was measured for 100 mW of input pump power. [ABSTRACT FROM AUTHOR]