Truthful Mechanisms for Secure Communication in Wireless Cooperative System

To ensure security in data transmission is one of the most important issues for wireless relay networks, and physical layer security is an attractive alternative solution to address this issue. In this paper, we consider a cooperative network, consisting of one source node, one destination node, one eavesdropper node, and a number of relay nodes. Specifically, the source may select several relays to help forward the signal to the corresponding destination to achieve the best security performance. However, the relays may have the incentive not to report their true private channel information in order to get more chances to be selected and gain more payoff from the source. We propose a Vickey-Clark-Grove (VCG) based mechanism and an Arrow-d'Aspremont-Gerard-Varet (AGV) based mechanism into the investigated relay network to solve this cheating problem. In these two different mechanisms, we design different "transfer payment" functions to the payoff of each selected relay and prove that each relay gets its maximum (expected) payoff when it truthfully reveals its private channel information to the source. And then, an optimal secrecy rate of the network can be achieved. After discussing and comparing the VCG and AGV mechanisms, we prove that the AGV mechanism can achieve all of the basic qualifications (incentive compatibility, individual rationality and budget balance) for our system. Moreover, we discuss the optimal quantity of relays that the source node should select. Simulation results verify efficiency and fairness of the VCG and AGV mechanisms, and consolidate these conclusions.Comment: To appear in IEEE Transactions on Wireless Communication

A Novel Approach to Transport-Layer Security for Spacecraft Constellations

Spacecraft constellations seek to provide transformational services from increased environmental awareness to reduced-latency international finance. This connected future requires trusted communications. Transport-layer security models presume link characteristics and encapsulation techniques that may not be sustainable in a networked constellation. Emerging transport layer protocols for space communications enable new transport security protocols that may provide a pragmatic alternative to deploying Internet security mechanisms in space. The Bundle Protocol (BP) and Bundle Protocol Security (BPSec) protocol have been designed to provide such an alternative. BP is a store-and-forward alternative to IP that carries session information as secondary headers. BPSec uses BP’s featureful secondary header mechanism to hold security information and security results. In doing so, BPSec provides an in-packet augmentation alternative to security by encapsulation. BPSec enables features such as security-at-rest, separate encryption/signing of individual protocol headers, and the ability to add secondary headers and secure them at waypoints in the network. These features provided by BPSec change the system trades associated with networked constellations. They enable security at rest, secure content caching, and deeper inspection at gateways otherwise obscured by tunneling

Financing agricultural inputs in Northern Togo through an inventory credit system: an economic analysis of institutional response

Agricultural intensification is widely seen as a condition sine-qua-non for enhanced food security and as a major driver for overall economic growth in sub-Saharan Africa (SSA). In this process, the financial system has an important role to play, especially to finance agricultural inputs. However in SSA, the financial institutions initiated by governments and donors have in general not lived up to the expectations, in particular not for the agricultural sector, because of inappropriate design and weaknesses in implementation. Even the microfinance institutions which were supposed to support the small-scale farmers have deflected for their goals due to the risks that the agricultural sector represents. To date, the economic research tends to concentrate on the mechanisms that secure the credit of microfinance institutions. However, the effective implementation of new mechanisms to secure credit appears more difficult than foreseen, as the decision making processes involved are complex and constrained by the lack of information. This paper argues that sustainable agricultural financing needs alternative schemes that secure both the credit of financial institutions and farmers’ income. It will also be shown how the new institutional economics perspective can be used to analyze and guide decision-making with respect to alternative schemes for agricultural financing. This paper which is based on quantitative and qualitative data presents the case of the inventory credit scheme on maize to facilitate access to agricultural inputs in Savannah region of Togo. In conclusion, some research areas will be indicated to improve our understanding of the inventory credit system.Financing, agricultural inputs, inventory credit, Togo, Agricultural and Food Policy, Crop Production/Industries, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, International Relations/Trade, Livestock Production/Industries, Marketing, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy,

SBVLC:Secure Barcode-based Visible Light Communication for Smartphones

2D barcodes have enjoyed a significant penetration rate in mobile applications. This is largely due to the extremely low barrier to adoption – almost every camera-enabled smartphone can scan 2D barcodes. As an alternative to NFC technology, 2D barcodes have been increasingly used for security-sensitive mobile applications including mobile payments and personal identification. However, the security of barcode-based communication in mobile applications has not been systematically studied. Due to the visual nature, 2D barcodes are subject to eavesdropping when they are displayed on the smartphone screens. On the other hand, the fundamental design principles of 2D barcodes make it difficult to add security features. In this paper, we propose SBVLC - a secure system for barcode-based visible light communication (VLC) between smartphones. We formally analyze the security of SBVLC based on geometric models and propose physical security enhancement mechanisms for barcode communication by manipulating screen view angles and leveraging user-induced motions. We then develop three secure data exchange schemes that encode information in barcode streams. These schemes are useful in many security-sensitive mobile applications including private information sharing, secure device pairing, and contactless payment. SBVLC is evaluated through extensive experiments on both Android and iOS smartphones

Icebergs in the Clouds: the Other Risks of Cloud Computing

Cloud computing is appealing from management and efficiency perspectives, but brings risks both known and unknown. Well-known and hotly-debated information security risks, due to software vulnerabilities, insider attacks, and side-channels for example, may be only the "tip of the iceberg." As diverse, independently developed cloud services share ever more fluidly and aggressively multiplexed hardware resource pools, unpredictable interactions between load-balancing and other reactive mechanisms could lead to dynamic instabilities or "meltdowns." Non-transparent layering structures, where alternative cloud services may appear independent but share deep, hidden resource dependencies, may create unexpected and potentially catastrophic failure correlations, reminiscent of financial industry crashes. Finally, cloud computing exacerbates already-difficult digital preservation challenges, because only the provider of a cloud-based application or service can archive a "live," functional copy of a cloud artifact and its data for long-term cultural preservation. This paper explores these largely unrecognized risks, making the case that we should study them before our socioeconomic fabric becomes inextricably dependent on a convenient but potentially unstable computing model.Comment: 6 pages, 3 figure

Improving Land Tenure Security through Customary Boundary Demarcation- A Case Study

In sub-Saharan Africa, one of the barriers to development and wealth creation in the peri urban and rural areas is land tenure insecurity. This is mainly due to a number of factors including the absence of clear unambiguous boundaries between allodial owners and the absence of credible documentation of land rights. This research sought to establish and document over 190 km of the boundary of Juaben paramouncy in a manner that ensured peace, harmony and tenure security. Disputes were resolved through less costly Alternative Dispute Resolution (ADR) mechanisms and Customary Land Secretariat (CLS) that catalogued and maintained up to date register on the land. This resulted in conflicts that have raged on for decades, sometimes leading to injury, property destruction and loss of lives come to an end. The benefits of this improved land tenure security are enhanced agricultural productivity, wealth creation for rural dwellers, peace and stability. Boundary demarcations and documentations established were important steps in the process of reformation and improving land tenure security in the rural communities. Information retrieval was simplified and transaction cost made cheaper. Keywords: Land Tenure Security, Customary Boundary Demarcation (CBD), Alternative Dispute Resolution (ADR

Physical-Layer Security Enhancement in Wireless Communication Systems

Without any doubt, wireless infrastructures and services have fundamental impacts on every aspect of our lives. Despite of their popularities, wireless communications are vulnerable to various attacks due to the open nature of radio propagation. In fact, communication security in wireless networks is becoming more critical than ever. As a solution, conventional cryptographic techniques are deployed on upper layers of network protocols. Along with direct attacks from lower layer, wireless security challenges come with the rapid evolution of sophisticated decipher techniques. Conventional security mechanisms are not necessarily effective against potential attacks from the open wireless environment anymore. As an alternative, physical-layer(PHY) security, utilizing unique features from lower layer, becomes a new research focus for many wireless communication systems. In this thesis, three mechanisms for PHY security enhancement are investigated. Beginning with a discussion on the security vulnerability in highly standardized infrastructures, the thesis proposed a time domain scrambling scheme of orthogonal frequency division multiplexing (OFDM) system to improve the PHY security. The method relies on secretly scrambling each OFDM symbol in time domain, resulting in constellation transformation in frequency domain, to hide transmission features. As a complement to existing secrecy capacity maximization based optimal cooperative jamming systems, a security strategy based on the compromised secrecy region (CSR) minimization in cooperative jamming is then proposed when instantaneous channel state information(CSI) is not available. The optimal parameters of the jammer are derived to minimize the CSR which exhibits high secrecy outage probability. At last, security enhancement of OFDM system in cooperative networks is also investigated. The function selection strategies of cooperative nodes are studied. Our approach is capable of enhancing the security of broadband communications by selecting the proper function of each cooperative node. Numerical results demonstrate the feasibility of three proposed physical layer security mechanisms by examining the communication reliability, achievable CSR and secrecy capacity respectively

PCA based components selection criteria for computationally efficient Physical Layer Key Generation (PLKG) system

Data security is one of the prime concerns in wireless networks. PLKG has been emerging as an attractive alternative to traditional cryptographic techniques. PLKG is more computationally efficient than cryptography. Moreover, PLKG using Principal component analysis (PCA) as pre-processing may further save computations. This paper proposes three mechanisms to select components of PCA which are based on Information content, Mean and Histfit. Bit Disagreement Rate (BDR) is compared for each mechanism. Histfit based method is found to be best. Since only two components are supposed to be processed for key generation, it is computationally efficient/ power efficient too