The token economy is a form of decentralized digital economy with the support of blockchain. In the token economy, the responsibility, rights and interests in the real economy can be solidified on the blockchain to form true digital commitments with consensus, tamper-resistance, traceability and verification. These commitments can not only enhance the mutual trust between economic entities, but also realize the isomorphism of real economic activities and digital economic activities. Furthermore, they are conducive to improving the protection of property rights, strengthening the market's allocation of resources, realizing the fair distribution of benefits, strengthening the government's penetrating supervision, and creating a mutually beneficial business environment. Therefore, the token economy is expected to become a new form of digital economy with mutual trust and collective governance. To better illustrate the token economy, this paper introduces the concepts of blockchain, token and token economy, presents the reason why token economy could create a new form of digital economy with mutual trust and collective governance, and finally advances some suggestions on how to develop the token economy.

Personal credit scoring is a fundamental problem in Finance. It has a lot of emerging applications including Credit Card,Mortgage Loan and Automobile Credit, etc. Due to its importance , a lot of personal credit scoring methods have been proposed. Among many other aspects of a client,trade reference is a crucial aspect for an effective credit scoring. In a trade reference,the referee provides a score to describe the credit of the client with respect to the business between the client and the referee. Most existing methods assume that the trade reference is trustable. However,the trade referee may conspire with the client and the trade reference score becomes untrustable in practice. Therefore, in this paper, we propose a trade referee rank to capture both the reputation of the trade referee and the trade reference score provided by the referee. The accuracy of using our trade reference rank is about 40% higher than that of the existing methods. We propose a random walk based method on a client reference graph to compute the trade reference rank of the clients. Our extensive experiments techniques.

There exist many unsolved problems in the traditional digital rights management of network media. For example, in the traditional management system it is hard to guarantee the quality of media works, to protect the copyrights, to find the effective profit model and so on. To solve these problems, we propose in this paper a network media's digital rights management scheme based on blockchain. Blockchain is a technology that makes use of cryptographic algorithm, hash chains and consensus mechanism to implement consensus, irreversibility and traceability for online data. The proposed scheme can use these functionalities of blockchain to implement the effective production management, copyright management, transaction management and users' behavior management for network media. Furthermore, our proposed scheme can predictively provide an important support for the network media platform to build a sustainable development of benign ecological environment.

Blockchain is a technology of recording ledgers in a distributed manner. It uses a consensus mechanism, digital signature and hash chains to realize the reliable storage of ledgers, and provide services such as traceability, integrity and no-repudiation for transactions in ledgers in a decentralized way. These services make blockchain have great application potentiality in the fields of healthcare, Fintech, computational law and so on. Before wide spreading its applications, blockchain must solve problems such as efficiency and privacy. Among these problems the privacy is an important one. Because blocks on blockchain are open, when transactions in blocks involve privacy data, these data can be leaked. Thus, certain security mechanisms must be built to protect privacy data. The core of these mechanisms is the appropriate key management schemes. However, blockchain is a developing technology, and few studies have been done on key management schemes for it. Because healthcare is a big application scenario of blockchain, in this paper, according to the features of health blockchain, we use body sensor network to design a lightweight backup and efficient recovery scheme for keys of health blockchain. Analyses show that the scheme has high security and performance, and it can be used to protect privacy messages on health blockchain effectively and to promote the application of health blockchain.

Body sensor networks (BSNs) are deployed around the human body to measure and process physiological signals in real time, which have wide application prospects in intelligent healthcare. Physiological signals measured and processed by BSNs involve individual privacy, thus security mechanisms must be developed to secure BSNs, and therein adoption of key negotiation protocols is fundamental. Due to stringently limited operation resources, BSNs require these protocols to be low-energy and highly efficient. Recent development has discovered that certain physiological signals can be used for efficiently negotiating common keys among biosensor nodes. These signals and fuzzy technology are used to design lightweight key negotiation protocols, and many solutions have been proposed. In this paper, we explore and classify these solutions, and evaluate their performance by analyzing their merits and demerits. Finally, we present open research issues that should be solved in the future.

Body sensor networks (BSNs) are distributed systems where biosensor nodes are distributed in different positions to collect health data from the human body and deliver the information to a remote medical center. Due to medical data regulations, security of BSNs is very important. However, the operational resources of biosensor nodes in BSNs are very restricted, and traditional security technologies are not directly applicable to BSNs. Due to characteristics of biosensors, time synchronization and low-energy communication are two challenging problems for BSNs. In this paper, a fuzzy commitment technology with weak time synchronization mechanism for keys negotiation is developed, with a multihop route key management scheme proposed for efficient energy consumption management, including an energy-based multihop-route-choice method. Security analyses and performance evaluation have been provided to validate the proposed scheme.

Oblivious Transfer protocol (OTP) is a paramount important primitive tool in modern cryptography. Essentially, OTP can be used to construct a secure multi-party computation protocol and distributed oblivious transfer protocol (DOTP). DOTP is the general OTP in the distributed setting. Private information retrieval (PIR) and symmetric private information retrieval (SPIR) problems are also analogous to those of the OTP. Due to its importance, the task of constructing efficient and secure OTP has attracted a lot interests. In this paper, a paradigm of OPT protocol and a practical fully-simulatable OTP protocol based on blind GDH (Gap Diffie-Hellman) signature are presented. The proposed schemes can achieve higher efficiency and better security than the popular Malkhi & Sella scheme. The salient property of short signature length of GDH signature scheme enables our proposals applicable to low-bandwidth communication environments.

Many wireless sensor networks (WSNs) consist of a large number of distributed sensor nodes that are batteries powered, vulnerable to tampering, and equipped with limited computational capabilities and memory. These characteristics render WSNs facing many security threats, which require cryptographic security mechanisms for secure communication, key revocation and management of security issues arising from the addition of new nodes. In this paper, we propose a key management scheme to meet the security requirements of wireless sensor networks. The scheme relies on the theory of random graph to build a fully secure connectivity for distributed sensor nodes. It uses heterogeneous structure to limit ranges of attacks, and utilizes hash chains to realize authentication of pool keys and broadcast messages of auxiliary nodes. The security and network connectivity characteristics supported by the key management scheme are discussed and simulation experiments are presented.