Blockchain-Based Secure and Fair IoT Data Trading System with Bilateral Authorization

These days,data is regarded as a valuable asset in the era of the data economy,which demands a trading platform for buying and selling data.However,online data trading poses challenges in terms of security and fairness because the seller and the buyer may not fully trust each other.Therefore,in this paper,a blockchain-based secure and fair data trading system is proposed by taking advantage of the smart contract and matchmaking encryption.The proposed system enables bilateral authorization,where data trading between a seller and a buyer is accomplished only if their policies,required by each other,are satisfied simultaneously.This can be achieved by exploiting the security features of the matchmaking encryption.To guarantee non-repudiation and fairness between trading parties,the proposed system leverages a smart contract to ensure that the parties honestly carry out the data trading protocol.However,the smart contract in the proposed system does not include complex cryptographic operations for the efficiency of onchain processes.Instead,these operations are carried out by off-chain parties and their results are used as input for the on-chain procedure.The system also uses an arbitration protocol to resolve disputes based on the trading proof recorded on the blockchain.The performance of the protocol is evaluated in terms of off-chain computation overhead and on-chain gas consumption.The results of the experiments demonstrate that the proposed protocols can enable the implementation of a cost-effective data trading system.

Trade versus Security: Sino-Israeli Security Relations in a Game of Three Players

Israel faces the classical question of the“trade versus security”dilemma in conducting security relations with China.In the context of such a dilemma,the article provides a new lens to understand the historical development of Sino-Israeli security relations by analyzing certain aspects of Sino-Israeli security relations,namely the trade-off between security and trade concerns,the intertwinement of domestic politics and alliance politics.The historical development of Sino-Israeli security relations verifies the determining role of the US in such a game of three players.Although under US pressure,Israel severed all military transfers to China,the general business relations with China holds a promising future.

China’s Food Security and International Trade

Since ancient times, the Chinese government has always attached a great deal of importance to food security . However, the problems have been different at different times, with a variety of different solutions. For a considerably long period of time, production efficiency was low due to the planned economy. Food supply was in a constant state of shortage due to limited investment,

EXISTENCE OF STOCHASTIC EQUILIBRIUM WITH INCOMPLETE FINANCIAL MARKETS

This paper analyzes the aritrage free security markets and the general equilibrium existence problem for a stochastic economy with incomplete financial markets. Information structure is given by an event tree. This paper restricts attention to purely financial securities. It is assume that trading takes place in the sequence of spot markets and futures markets for securities payable in units of account. Unlimited short selling in securities is allowed. Financial markets may be incomplete: some consumption streams may be impossible to obtain by any trading strategy. Securities may be individually precluded from trade at arbitrary states and dates. The security price process is arbitrage free the dividend process if and only if there exists a stochstic state price (present value) process: the present value of the security prices at every vertex is the present value of their dividend and capital values over the set of immediate successors; the current value of each security at every vertex is the present value of its future dividend stream over all succeeding vertices. The existence of such an equilibrium is proved under the following condition: continuous, weakly convex, strictly monotone and complete preferences, strictly positive endowments and dividends processes.

Is the ‘Circuit Breaker’ to Blame for the Stock Market Fall?

In an effort to tame the frenzied stock market last year,the China Securities Regulatory Commission（CSRC）implemented a＂circuit breaker＂mechanism to mitigate the impact of future fluctuations.The mechanism started operating on January 4,but was subsequently responsible for the early end of the first day of trading in 2016.