The Private Key Capacity of a Cooperative Pairwise-Independent Network

This paper studies the private key generation of a cooperative pairwise-independent network (PIN) with M+2 terminals (Alice, Bob and M relays), M >= 2. In this PIN, the correlated sources observed by every pair of terminals are independent of those sources observed by any other pair of terminal. All the terminals can communicate with each other over a public channel which is also observed by Eve noiselessly. The objective is to generate a private key between Alice and Bob under the help of the M relays; such a private key needs to be protected not only from Eve but also from individual relays simultaneously. The private key capacity of this PIN model is established, whose lower bound is obtained by proposing a novel random binning (RB) based key generation algorithm, and the upper bound is obtained based on the construction of M enhanced source models. The two bounds are shown to be exactly the same. Then, we consider a cooperative wireless network and use the estimates of fading channels to generate private keys. It has been shown that the proposed RB-based algorithm can achieve a multiplexing gain M-1, an improvement in comparison with the existing XOR- based algorithm whose achievable multiplexing gain is about [M]/2.Comment: 5 pages, 3 figures, IEEE ISIT 2015 (to appear

A study of An Apologeticall Narration (1643/4): with particular consideration of the contributions of Elizabethan and Jacobean puritanism and New England and Dutch congregationalism to the rise of the "congregational way" in England in the 1640s and 1650s

This thesis is a study of the "Congregational way" in England as briefly presented by the "five dissenting brethren" in the Apologeticall Narration (1643/4). It sets out to analyse how the "congregational" impulse in Elizabethan and Jacobean puritanism, the Congregational propaganda in New England, and the Congregational experiment and liberal thought in Holland concurred to bring about the Congregational churches in the England of the 1640s and 1650s. The introduction presents the full historical milieu or context that produced the dissenting brethren's apologia. The first chapter deals with the Congregationals' view of church membership and their debate with the Presbyterians on the admission issue. The second chapter assesses their attitudes towards the state and the mainline churches (the Church of England and Reformed Churches) and examines their church worship and ministry. The third chapter looks at their view of church government or discipline and their debate with the Presbyterians on church order. The fourth chapter investigates their protological and eschatological understanding of the church. The final chapter explores their belief in the soteriological significance of churchmanship; this is followed by the analysis of their theory of religious toleration, which had its origins in Holland, and their "denominationalism". The conclusions of the above chapters concerning the tenets and roots of the Congregational way are drawn together in the general conclusion, in which there is also a brief survey of the rise of the Congregational churches in the England of the 1640s and 1650s, and a short discussion of the impact of the apologia on both Cromwell's religious policy in England and Locke's theoretical defence of religious toleration

Organization and Strategy of Farmer Specialized Cooperatives in China

A description and analysis of China's Farmer Specialized Cooperatives is presented. Data is presented regarding the historical development of farmer cooperatives in China, the membership composition of a sample of 66 farmer cooperatives in the Zhejiang province, and the various attributes (governance, quality control system, and strategy) of a watermelon cooperative in this province. Many cooperatives are being transformed in organizations with a market orientation. These cooperatives exhibit substantial heterogeneity, in terms of farmers being member and skewness in the distribution of control rights. Human asset specificity in terms of establishing and maintaining relations and access to markets seems to be more important than physical asset specificity in accounting for governance structure choice in the current institutional setting.Farmer Cooperative, China, Governance Structure, Business Strategy, Agribusiness, Q13,

Optimal precoding for a QoS optimization problem in two-user MISO-NOMA downlink

In this letter, based on the non-orthogonal multiple access (NOMA) concept, a quality-of-service optimization problem for two-user multiple-input-single-output broadcast systems is considered, given a pair of target interference levels. The minimal power and the optimal precoding vectors are obtained by considering its Lagrange dual problem and via Newton's iterative algorithm, respectively. Moreover, the closed-form expressions of the minimal transmission power for some special cases are also derived. One of these cases is termed quasi-degraded, which is the key point and will be discussed in detail in this letter. Our analysis further figures out that the proposed NOMA scheme can approach nearly the same performance as optimal dirty paper coding, as verified by computer simulations

On the private key capacity of the M-Relay pairwise independent network

We study the problem of private key generation in a cooperative pairwise independent network (PIN), with M + 2 terminals (Alice, Bob, and M relays), M ≥ 2. In the PIN, the correlated source observed by every pair of terminals is independent of the sources observed by any other pairs of terminals. Moreover, all terminals can communicate with each other over a public channel, which is also observed by Eve, noiselessly. The objective is to generate a private key between Alice and Bob with the help of the M relays; such a private key needs to be protected not only from Eve but also from all relays. A single-letter expression for the private key capacity of this PIN model is obtained, where the achievability part is established by proposing a random binning (RB)-based key generation algorithm, and the converse part is established by deriving upper bounds of M enhanced source models. Next, we consider a cooperative wireless network and use the estimates of fading channels to generate private keys. It has been shown that the proposed RB key generation algorithm can achieve a multiplexing gain of M - 1, which is an improvement compared with the existing XOR algorithm, whose achievable multiplexing gain is IM/2J

Simultaneously generating secret and private keys in a cooperative pairwise-independent network

This paper studies the problem of simultaneously generating a secret key (SK) and a private key (PK) between Alice and Bob, in a cooperative pairwise-independent network (PIN) with two relays. In the PIN, the pairwise source observed by every pair of terminals is independent of those sources observed by any other pairs. The SK needs to be protected from Eve, while the PK needs to be protected not only from Eve but also from the two relays. Two cooperative SK-PK generation algorithms are proposed: both of them first generate common randomness, based on the well-established pairwise key generation technique and the application of the one-time pad; but then, the two algorithms utilize the XOR operation and a specific random-binning-based SK-PK codebook to generate the expected keys, respectively. The achievable SK-PK rate regions of both the two proposed algorithms are analyzed. Of particular interest is the second algorithm with random-bing based codebook, whose achievable key rate region is demonstrated to be exactly the same as the derived outer bound, a crucial step for establishing the key capacity of this PIN model. Finally, the two proposed SK-PK generation algorithms are extended to a cooperative wireless network, where the correlated source observations are obtained from estimating wireless channels during a training phase

Group Secret Key Generation in Wireless Networks : Algorithms and Rate Optimization

This paper investigates group secret key generation problems for different types of wireless networks, by exploiting physical layer characteristics of wireless channels. A new group key generation strategy with low complexity is proposed, which combines the well-established point-to-point pairwise key generation technique, the multisegment scheme, and the one-time pad. In particular, this group key generation process is studied for three types of communication networks: 1) the three-node network; 2) the multinode ring network; and 3) the multinode mesh network. Three group key generation algorithms are developed for these communication networks, respectively. The analysis shows that the first two algorithms yield optimal group key rates, whereas the third algorithm achieves the optimal multiplexing gain. Next, for the first two types of networks, we address the time allocation problem in the channel estimation step to maximize the group key rates. This non-convex max-min time allocation problem is first reformulated into a series of geometric programming, and then, a single-condensation-method-based iterative algorithm is proposed. Numerical results are also provided to validate the performance of the proposed key generation algorithms and the time allocation algorithm