Usually, a proof of a theorem contains more knowledge than the mere fact that the theorem is true. For instance, to prove that a graph is Hamiltonian it suffices to exhibit a Hamiltonian tour in it; however, this seems to contain more knowledge than the single bit Hamiltonian/non-Hamiltonian.In this paper a computational complexity theory of the “knowledge” contained in a proof is developed. Zero-knowledge proofs are defined as those proofs that convey no additional knowledge other than the correctness of the proposition in question. Examples of zero-knowledge proof systems are given for the languages of quadratic residuosity and 'quadratic nonresiduosity. These are the first examples of zero-knowledge proofs for languages not known to be efficiently recognizable.

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The knowledge complexity of interactive proof-systems

The past decade has witnessed the rapid evolution in blockchain technologies, which has attracted tremendous interests from both the research communities and industries. The blockchain network was originated from the Internet financial sector as a decentralized, immutable ledger system for transactional data ordering. Nowadays, it is envisioned as a powerful backbone/framework for decentralized data processing and data-driven self-organization in flat, open-access networks. In particular, the plausible characteristics of decentralization, immutability, and self-organization are primarily owing to the unique decentralized consensus mechanisms introduced by blockchain networks. This survey is motivated by the lack of a comprehensive literature review on the development of decentralized consensus mechanisms in blockchain networks. In this paper, we provide a systematic vision of the organization of blockchain networks. By emphasizing the unique characteristics of decentralized consensus in blockchain networks, our in-depth review of the state-of-the-art consensus protocols is focused on both the perspective of distributed consensus system design and the perspective of incentive mechanism design. From a game-theoretic point of view, we also provide a thorough review of the strategy adopted for self-organization by the individual nodes in the blockchain backbone networks. Consequently, we provide a comprehensive survey of the emerging applications of blockchain networks in a broad area of telecommunication. We highlight our special interest in how the consensus mechanisms impact these applications. Finally, we discuss several open issues in the protocol design for blockchain consensus and the related potential research directions.

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A Survey on Consensus Mechanisms and Mining Strategy Management in Blockchain Networks

Purpose: This paper investigates the way in which blockchain technology is likely to influence future supply chain practices and policies. Design/methodology/approach: A systematic review of both academic and practitioner literature was conducted. Multiple accounts of blockchain adoption within industry were also consulted to gain further insight. Findings: While blockchain technologies remain in their infancy, they are gaining momentum within supply chains, trust being the predominant factor driving their adoption. The value of such technologies for supply chain management lies in four areas: extended visibility and traceability, supply chain digitalisation and disintermediation, improved data security and smart contracts. Several challenges and gaps in understanding and opportunities for further research are identified by our research. How a blockchain enabled supply chain should be configured has also been explored from a design perspective. Research limitations/implications: Our systematic review focuses on the diffusion of blockchain technology within supply chains and great care was taken in selecting search terms. However, we acknowledge that our choice of terms may have excluded certain blockchain articles from this review. Practical implications: This paper offers valuable insight for supply-chain practitioners into how blockchain technology has the potential to disrupt existing supply chain provisions as well as a number of challenges to its successful diffusion. Originality/value: Ours is one of the first studies to examine the current state of blockchain diffusion within supply chains. It lays a firm foundation for future research. Keywords: blockchain, distributed ledger technology, supply chain management, peer-to-peer communication, systematic literature review

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Understanding blockchain technology for future supply chains: a systematic literature review and research agenda

Recently, artificial intelligence (AI) and blockchain have become two of the most trending and disruptive technologies. Blockchain technology has the ability to automate payment in cryptocurrency and to provide access to a shared ledger of data, transactions, and logs in a decentralized, secure, and trusted manner. Also with smart contracts, blockchain has the ability to govern interactions among participants with no intermediary or a trusted third party. AI, on the other hand, offers intelligence and decision-making capabilities for machines similar to humans. In this paper, we present a detailed survey on blockchain applications for AI. We review the literature, tabulate, and summarize the emerging blockchain applications, platforms, and protocols specifically targeting AI area. We also identify and discuss open research challenges of utilizing blockchain technologies for AI.

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Blockchain for AI: Review and Open Research Challenges

Neuromorphic computing has come to refer to a variety of brain-inspired computers, devices, and models that contrast the pervasive von Neumann computer architecture This biologically inspired approach has created highly connected synthetic neurons and synapses that can be used to model neuroscience theories as well as solve challenging machine learning problems The promise of the technology is to create a brain-like ability to learn and adapt, but the technical challenges are significant, starting with an accurate neuroscience model of how the brain works, to finding materials and engineering breakthroughs to build devices to support these models, to creating a programming framework so the systems can learn, to creating applications with brain-like capabilities In this work, we provide a comprehensive survey of the research and motivations for neuromorphic computing over its history We begin with a 35-year review of the motivations and drivers of neuromorphic computing, then look at the major research areas of the field, which we define as neuro-inspired models, algorithms and learning approaches, hardware and devices, supporting systems, and finally applications We conclude with a broad discussion on the major research topics that need to be addressed in the coming years to see the promise of neuromorphic computing fulfilled The goals of this work are to provide an exhaustive review of the research conducted in neuromorphic computing since the inception of the term, and to motivate further work by illuminating gaps in the field where new research is needed

A Survey of Neuromorphic Computing and Neural Networks in Hardware.

As more applications are built on top of blockchain and public ledger, different approaches are developed to improve the performance of blockchain construction. Recently Intel proposed a new concept of proof-of-elapsed-time (PoET), which leverages trusted computing to enforce random waiting times for block construction. However, trusted computing component may not be perfect and 100% reliable. It is not clear, to what extent, blockchain systems based on PoET can tolerate failures of trusted computing component. The current design of PoET lacks rigorous security analysis and a theoretical foundation for assessing its strength against such attacks. To fulfill this gap, we develop a theoretical framework for evaluating a PoET based blockchain system, and show that the current design is vulnerable in the sense that adversary can jeopardize the blockchain system by only compromising \(\varTheta (\log \log n/\log n)\) fraction of the participating nodes, which is very small when n is relatively large. Based on our theoretical analysis, we also propose methods to mitigate these vulnerabilities.

On Security Analysis of Proof-of-Elapsed-Time (PoET)

We propose CL-PRE, a certificateless proxy re-encryption scheme for secure data sharing with public cloud, which leverages maximal cloud resources to reduce the computing and communication cost for data owner. Towards running proxy in public cloud environment, we further propose multi-proxy CL-PRE and randomized CL-PRE, which enhance the security and robustness of CL-PRE. We implement all CL-PRE schemes and evaluate their security and performance.

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CL-PRE: a certificateless proxy re-encryption scheme for secure data sharing with public cloud

Blockchain is a novel way to construct fully distributed systems and has the potential to disrupt many businesses including Uber and Airbnb within the sharing economy. Specifically, blockchain provides a method to enforce the agreement between a user and the physical property owner without using any trusted party, e.g., if a user pays the agreed money, the blockchain guarantees that he/she has access to the property. While a blockchain based system has many desirable features, it may leak privacy information of involved parties due to its openness to the public. To mitigate the privacy concern, we propose a privacy respecting approach for blockchain-based sharing economy applications, which leverages a zero-knowledge scheme. We also analyze the security features and performance of the proposed approach to demonstrate its effectiveness in these applications.

Enabling the Sharing Economy: Privacy Respecting Contract based on Public Blockchain

Modern supply chain is a complex system and plays an important role for different sectors under the globalization economic integration background. Supply chain management system is proposed to handle the increasing complexity and improve the efficiency of flows of goods. It is also useful to prevent potential frauds and guarantee trade compliance. Currently, most companies maintain their own IT systems for supply chain management. However, it is hard for these isolated systems to work together and provide a global view of the status of the highly distributed supply chain system. Using emerging decentralized ledger/blockchain technology, which is a special type of distributed system in essence, to build supply chain management system is a promising direction to go. Decentralized ledger usually suffers from low performance and lack of capability to protect information stored on the ledger. To overcome these challenges, we propose CoC (supply chain on blockchain), a novel supply chain management system based on a hybrid decentralized ledger with a novel two-step block construction mechanism. We also design an efficient storage scheme and information protection method that satisfy requirements of supply chain management. These techniques can also be applied to other decentralized ledger based applications with requirements similar to supply chain management.

CoC: A Unified Distributed Ledger Based Supply Chain Management System

E-government system has greatly improved the efficiency and transparency of daily operations of a government. However, most of existing e-government services are provided in a centralized manner and heavily rely on human individuals to control. The highly centralized IT infrastructure is more vulnerable to outside attacks. Also, it is relatively easy to compromise the data integrity by inside rogue users. Furthermore, relying on individuals to monitor and control some of the working flows makes the system error-prone and leaves room for corruption. To address these challenges, we propose to use the blockchain technology and decentralized autonomous organization (DAO) to improve the e-government system. The blockchain-based DAO system works in a fully decentralized way and is immune to both outside and inside attacks. At the same time, operations of such system is only controlled by pre-defined rules; thus, the uncertainty and errors caused by human processes are greatly reduced. We provide a concrete use case to demonstrate the usage of DAO e-government and evaluate its effectiveness.

Lei Xu

Papers

On Security Analysis of Proof-of-Elapsed-Time (PoET)

CL-PRE: a certificateless proxy re-encryption scheme for secure data sharing with public cloud

Enabling the Sharing Economy: Privacy Respecting Contract based on Public Blockchain

CoC: A Unified Distributed Ledger Based Supply Chain Management System

eGov-DAO: a Better Government using Blockchain based Decentralized Autonomous Organization