As in 2009 the first encrypted electronic currency Bitcoin is introduced, the block chain technology has received attention. Bitcoin is a currency issued without a trusted third party, in peer-to-peer (Peer-to-Peer) network and gives a guarantee of the reliability of money transactions, ensures the integrity of transactions. There is a back end-technique called block-chain that guarantees these without trusted third party. Block chain is a public ledger that all nodes to verify transactions and maintain integrity with the same ledger. Block chain technology applies not only electronic currency but also in various industries such as contract document integrity, cloud storage service, internet of thigns, supply chain for transaction integrity. However, there are problems to be solved if the bitcoin block chain consensus rule is applied to these industry. First, there is problem of low transaction throughput and block generation rate by an inefficient consensus rule. Second, There is problem of tampered block broadcast with non-dependency (internet of things data, food history data) transactions when applying the block chain consensus rule, which is proof-of-work of bitcoin's competitive system.
Anunay Kulshrestha, Akshay Rampuria, Matthew Denton, Ashwin Sreenivas
We introduce a robust framework that allows for cryptographically secure multiparty computations, such as distributed private value auctions. The security is guaranteed by two-sided authentication of all network connections, homomorphically encrypted bids, and the publication of zero-knowledge proofs of every computation. This also allows a non-participant verifier to verify the result of any such computation using only the information broadcasted on the network by each individual bidder. Building on previous work on such systems, we design and implement an extensible framework that puts the described ideas to practice. Apart from the actual implementation of the framework, our biggest contribution is the level of protection we are able to guarantee from attacks described in previous work. In order to provide guidance to users of the library, we analyze the use of zero knowledge proofs in ensuring the correct behavior of each node in a computation. We also describe the usage of the library to perform a private-value distributed auction, as well as the other challenges in implementing the protocol, such as auction registration and certificate distribution. Finally, we provide performance statistics on our implementation of the auction.
Daniel Conte de Leon, Antonius Q. Stalick, Ananth A. Jillepalli, Michael Haney · 5 authors
Purpose - The purpose of this article is to clarify current and widespread misconceptions about the properties of blockchain technologies and to describe challenges and avenues for correct and trustworthy design and implementation of distributed ledger system (DLS) or Technology (DLT). Design/methodology/approach - The authors contrast the properties of a blockchain with desired, however emergent, properties of a DLS, which is a complex and distributed system. They point out and justify, with facts and analysis, current misconceptions about the blockchain and DLSs. They describe challenges that these systems will need to address and possible solution avenues for achieving trustworthiness. Findings - Many of the statements that have appeared on the internet, news and academic articles, such as immutable ledger and exact copies, may be misleading. These are desired emergent properties of a complex system, not assured properties. It is well-known within the distributed systems and critical software community that it is extremely hard to prove that a complex system correctly and completely implements emergent properties. Further research and development for trustworthy DLS design and implementation is needed, both practical and theoretical. Research limitations/implications - This is the first known published attempt at describing current misconceptions about blockchain technologies. Further collaborative work, discussions, potential solutions, evaluations, resulting publications and verified reference implementations are needed to ensure DLTs are safe, secure, and trustworthy. Practical implications - Interdisciplinary teams with members from academia, business and industry, and from disciplines such as business, entrepreneurship, theoretical and practical computer science, cybersecurity, finance, mathematics and statistics, must be formed. Such teams must collaborate with the objective of developing strategies and techniques for ensuring the correctness and security of future DLSs in which our society may become dependent. Originality value - The value and originality of this article is twofold: the disproving, through fact collection and systematic analysis, of current misconceptions about the properties of the blockchain and DLSs, and the discussion of challenges to achieving adequate trustworthiness along with the proposal of general avenues for possible solutions.
Bitcoin's underlying blockchain database is a novel approach to recordkeeping that has the potential to decentralize big data. Bitcoin's success has inspired a multitude of spinoff projects hoping to use blockchain as a distributed database for records-management innovation in other fields. Misconceptions and exaggerations about blockchain and its capabilities are pervasive in the media. Drawing on perspectives from archival science, dependable computing, and secure computing, this paper surveys current applications, research, and critiques of blockchain to provide an objective assessment of its benefits and limitations. Based on the findings of the survey, this paper proposes three criteria that predict success for blockchain-based data management projects, briefly: dependability, security, and trust.
Zhiqing Huang, Xiongye Su, Yanxin Zhang, Changxue Shi · 6 authors
Internet of Things (IoT) plays an important role in the development of various fields. The increasing scale and scope of applications make a great demand of IoT data exchange in recent years. Meanwhile, a number of IoT data exchange platforms which dedicated to connecting various and distributed data sources are emerging. In such a platform, service providers can search and exchange the data sets that they need. However, the centralized infrastructure cannot provide enough trust as the third-party intermediaries for data exchange. As a result, most platforms unable to satisfy the complex requirements due to few institutions and individuals are willing to share their IoT data sets in such an untrustworthy environment. This paper proposes a decentralized solution based on the blockchain for IoT data trusted exchange. Specifically, In this paper, the basic principles of blockchain and corresponding key technologies are expounded through in-depth analysis of three main reliable requirements in IoT data exchange. Besides, this paper provides an architecture of above solution and detailed design of its main trust component. Finally, it realizes a prototype by using Ethereum blockchain and smart contracts and presents its auditable, transparent, decentralized features visually.
Otto Julio Ahlert Pinno, André Grégio, Luis C. E. Bona
The IoT is pervading our daily activities and lives with devices scattered all over our cities, transport systems, buildings, homes and bodies. This invasion of devices with sensors and communication capabilities brings big concerns, mainly about the privacy and confidentiality of the collected information. These concerns hinder the wide adoption of the IoT. To overcome them, in this work, we present an Blockchain-based architecture for IoT access authorizations. Following the IoT tendency requirements, our architecture is user transparent, user friendly, fully decentralized, scalable, fault tolerant and compatible with a wide range of today's access control models used in the IoT. Finally, our architecture also has a secure way to establish relationships between users, devices and group of both, allowing the assignment of attributes for these relationships and their use in the access control authorization.
The Internet of Things (IoT) has penetrated deeply into our lives and the number of IoT devices per person is expected to increase substantially over the next few years. Due to the characteristics of IoT devices (i.e., low power and low battery), usage of these devices in critical applications requires sophisticated security measures. Researchers from academia and industry now increasingly exploit the concept of blockchains to achieve security in IoT applications. The basic idea of the blockchain is that the data generated by users or devices in the past are verified for correctness and cannot be tampered once it is updated on the blockchain. Even though the blockchain supports integrity and non-repudiation to some extent, confidentiality and privacy of the data or the devices are not preserved. The content of the data can be seen by anyone in the network for verification and mining purposes. In order to address these privacy issues, we propose a new privacy-preserving blockchain architecture for IoT applications based on attribute-based encryption (ABE) techniques. Security, privacy, and numerical analyses are presented to validate the proposed model.
Blockchain has recently been applied in many applications such as bitcoin, smart grid, and Internet of Things (IoT) as a public ledger of transactions. However, the use of blockchain in mobile environments is still limited because the mining process consumes too much computing and energy resources on mobile devices. Edge computing offered by the Edge Computing Service Provider can be adopted as a viable solution for offloading the mining tasks from the mobile devices, i.e., miners, in the mobile blockchain environment. However, a mechanism needs to be designed for edge resource allocation to maximize the revenue for the Edge Computing Service Provider and to ensure incentive compatibility and individual rationality is still open. In this paper, we develop an optimal auction based on deep learning for the edge resource allocation. Specifically, we construct a multi-layer neural network architecture based on an analytical solution of the optimal auction. The neural networks first perform monotone transformations of the miners' bids. Then, they calculate allocation and conditional payment rules for the miners. We use valuations of the miners as the data training to adjust parameters of the neural networks so as to optimize the loss function which is the expected, negated revenue of the Edge Computing Service Provider. We show the experimental results to confirm the benefits of using the deep learning for deriving the optimal auction for mobile blockchain with high revenue
In this paper, we propose a zero-knowledge proof for a special case of the hidden subset sum problem. This problem was presented by [Boyko et al. 1998] as the underlying problem of methods for generating random pairs of the form (x, gx (mod p)) using precomputations. The proof we propose is an adaptation of a zero-knowledge protocol for the subset sum problem presented by [Blocki 2009].
A blockchain powered Health information ecosystem can solve a frequently discussed problem of the lifelong recorded patient health data, which seriously could hurdle the privacy of the patients and the growing data hunger of the research and policy maker institutions. On one side the general availability of the data is vital in emergency situations and supports heavily the different research, population health management and development activities, on the other side using the same data can lead to serious social and ethical problems caused by malicious actors. Currently, the regulation of the privacy data varies all over the world, however underlying principles are always defensive and protective towards patient privacy against general availability. The protective principles cause a defensive, data hiding attitude of the health system developers to avoid breaching the overall law regulations. It makes the policy makers and different - primarily drug - developers to find ways to treat data such a way that lead to ethical and political debates. In our paper we introduce how the blockchain technology can help solving the problem of secure data storing and ensuring data availability at the same time. We use the basic principles of the American HIPAA regulation, which defines the public availability criteria of health data, however the different local regulations may differ significantly. Blockchain's decentralized, intermediary-free, cryptographically secured attributes offer a new way of storing patient data securely and at the same time publicly available in a regulated way, where a well-designed distributed peer-to-peer network incentivize the smooth operation of a full-featured EHR system.
Used mainly for the virtual money, the Blockchain technology adopts a decentralized network of peers to ensure a secure and transparent information storage and transmission. The basic use of Blockchain can be bypassed, and it is interesting to integrate it into other fields such as the Cloud storage. Cloud storage solutions ensure a continuous data synchronization and guarantee data sharing between different users. However, sharing user side encrypted data raises key and access control management challenges. Within this paper, we propose a novel access control model called Timely CP-ABE. Two main features come with our model. First, we introduce a decentralized access control mechanism where the user legitimacy is verified by Blockchain nodes. Second, we add temporal dimension to file sharing based on CP-ABE. In fact, we introduce a validity time to the access authorization without additional revocation cost. As a proof of concept, the implementation of the Timely CP-ABE based on Blockchain is performed on the CP-ABE toolkit and Multichain solution.
Now, the authors’ life is full of vast amount of information, the era of information has arrived. So the content‐centric networks face severe challenges in dealing with a huge range of content requests, bringing protection and sharing concerns of the content. How to protect information in the network efficiently and securely for the upcoming 5G era has become a problem. The authors propose a scheme based on a blockchain to solve the privacy issues in content‐centric mobile networks for 5G. The authors implement the mutual trust between content providers and users. Besides, the openness and tamper‐resistant of the blockchain ledger ensure the access control and privacy of the provider. With the help of a miner, selected from users, the authors can maintain the public ledger expediently. Also, in return, the authors share the interesting data with low overhead, network delay and congestion, and then achieve green communication.
Blockchain Technology Applications and Security
Privacy-Preserving Technologies in Data
Advanced Steganography and Watermarking Techniques
Blockchain, an emerging decentralized security system, has been applied in many applications, such as bitcoin, smart grid, and Internet-of-Things. However, running the mining process may cost too much energy consumption and computing resource usage on handheld devices, which restricts the use of blockchain in mobile environments. In this paper, we consider deploying edge computing service to support the mobile blockchain. We propose an auction-based edge computing resource market of the edge computing service provider. Since there is competition among miners, the allocative externalities (positive and negative) are taken into account in the model. In our auction mechanism, we maximize the social welfare while guaranteeing the truthfulness, individual rationality and computational efficiency. Based on blockchain mining experiment results, we define a hash power function that characterizes the probability of successfully mining a block. Through extensive simulations, we evaluate the performance of our auction mechanism which shows that our edge computing resources market model can efficiently solve the social welfare maximization problem for the edge computing service provider.
Certification of keys and attributes is in practice typically realized by a hierarchy of issuers. Revealing the full chain of issuers for certificate verification, however, can be a privacy issue since it can leak sensitive information about the issuer's organizational structure or about the certificate owner. Delegatable anonymous credentials solve this problem and allow one to hide the full delegation (issuance) chain, providing privacy during both delegation and presentation of certificates. However, the existing delegatable credentials schemes are not efficient enough for practical use.
Ethan Cecchetti, Fan Zhang, Yan Ji, Ahmed E. Kosba · 6 authors
Blockchains and more general distributed ledgers are becoming increasingly popular as efficient, reliable, and persistent records of data and transactions. Unfortunately, they ensure reliability and correctness by making all data public, raising confidentiality concerns that eliminate many potential uses.
Muhammad Salek Ali, Koustabh Dolui, Fabio Antonelli
Blockchain, the underlying technology of cryptocurrency networks like Bitcoin, can prove to be essential towards realizing the vision of a decentralized, secure, and open Internet of Things (IoT) revolution. There is a growing interest in many research groups towards leveraging blockchains to provide IoT data privacy without the need for a centralized data access model. This paper aims to propose a decentralized access model for IoT data, using a network architecture that we call a modular consortium architecture for IoT and blockchains. The proposed architecture facilitates IoT communications on top of a software stack of blockchains and peer-to-peer data storage mechanisms. The architecture is aimed to have privacy built into it, and to be adaptable for various IoT use cases. To understand the feasibility and deployment considerations for implementing the proposed architecture, we conduct performance analysis of existing blockchain development platforms, Ethereum and Monax.
The mining process in blockchain requires solving a proof-of-work puzzle, which is resource expensive to implement in mobile devices due to the high computing power and energy needed. In this paper, we, for the first time, consider edge computing as an enabler for mobile blockchain. In particular, we study edge computing resource management and pricing to support mobile blockchain applications in which the mining process of miners can be offloaded to an edge computing service provider. We formulate a two-stage Stackelberg game to jointly maximize the profit of the edge computing service provider and the individual utilities of the miners. In the first stage, the service provider sets the price of edge computing nodes. In the second stage, the miners decide on the service demand to purchase based on the observed prices. We apply the backward induction to analyze the sub-game perfect equilibrium in each stage for both uniform and discriminatory pricing schemes. For the uniform pricing where the same price is applied to all miners, the existence and uniqueness of Stackelberg equilibrium are validated by identifying the best response strategies of the miners. For the discriminatory pricing where the different prices are applied to different miners, the Stackelberg equilibrium is proved to exist and be unique by capitalizing on the Variational Inequality theory. Further, the real experimental results are employed to justify our proposed model.
Public blockchain networks using proof of work (PoW)-based consensus protocols are considered as a promising platform for decentralized resource management with financial incentive mechanisms. In order to maintain a secured, universal state of the blockchain, PoW-based consensus protocols financially incentivize the nodes in the network to compete for the privilege of block generation through cryptographic puzzle solving. For rational consensus nodes, i.e., miners with limited local computational resources, offloading the computation load for PoW to the cloud/fog providers (CFPs) becomes a viable option. In this paper, we study the interaction between the CFPs and the miners in a PoW-based blockchain network using a game theoretic approach. In particular, we propose a lightweight infrastructure of the PoW-based blockchains, where the computation-intensive part of the consensus process is offloaded to the cloud/fog. We formulate the computation resource management in the blockchain consensus process as a two-stage Stackelberg game, where the profit of the CFP and the utilities of the individual miners are jointly optimized. In the first stage of the game, the CFP sets the price of offered computing resource. In the second stage, the miners decide on the amount of service to purchase accordingly. We apply backward induction to analyze the subgame perfect equilibria in each stage for both uniform and discriminatory pricing schemes. For uniform pricing where the same price applies to all miners, the uniqueness of the Stackelberg equilibrium is validated by identifying the best response strategies of the miners. For discriminatory pricing where the different prices are applied, the uniqueness of the Stackelberg equilibrium is proved by capitalizing on the variational inequality theory. Further, the real experimental results are employed to justify our proposed model.
Remo Manuel Frey, Pascal Bühler, Alexander Gerdes, Thomas Hardjono · 6 authors
In light of digitalization, customers increasingly share private data through their online behaviors and actions. Yet, customers have become reluctant to share data due to privacy concerns. From a psychological perspective, a reduction of users' perceived risks should result in a higher willingness to share sensitive data. The development of blockchain-supported, multi-part computation thereby represents an interesting novel empirical context to study such willingness to disclose personal data, as such technologies involve a privacy-preserving approach that could not only technically solve privacy issues but also ought to address precisely the user's risk perception. Therefore, we conducted an online experiment with 420 participants to examine the willingness to disclose personal data dependent on different privacy protection mechanisms. A deception based experiment allowed to measure not only user intention, but also real user behavior. Surprisingly, our results demonstrate that participants shared similar amounts of personal data for blockchain-supported approaches and standard privacy policies. Even though an aversion to the blockchain system due to its novelty and potentially perceived complexity was not detected. Furthermore, we found that the willingness to share data increased significantly specifically for technically affine people when they were presented with the opportunity to monetize their data. We further discuss the effects of privacy awareness and whether prior knowledge of blockchain technology had a supporting effect for user acceptance.
Blockchain has been applied to study data privacy and network security recently. In this paper, we propose a punishment scheme based on the action record on the blockchain to suppress the attack motivation of the edge servers and the mobile devices in the edge network. The interactions between a mobile device and an edge server are formulated as a blockchain security game, in which the mobile device sends a request to the server to obtain real-time service or launches attacks against the server for illegal security gains, and the server chooses to perform the request from the device or attack it. The Nash equilibria (NEs) of the game are derived and the conditions that each NE exists are provided to disclose how the punishment scheme impacts the adversary behaviors of the mobile device and the edge server.
Recent years have witnessed the trend of increasingly relying on distributed infrastructures. This increased the number of reported incidents of security breaches compromising users' privacy, where third parties massively collect, process and manage users' personal data. Towards these security and privacy challenges, we combine hierarchical identity based cryptographic mechanisms with emerging blockchain infrastructures and propose a blockchain-based data usage auditing architecture ensuring availability and accountability in a privacy-preserving fashion. Our approach relies on the use of auditable contracts deployed in blockchain infrastructures. Thus, it offers transparent and controlled data access, sharing and processing, so that unauthorized users or untrusted servers cannot process data without client's authorization. Moreover, based on cryptographic mechanisms, our solution preserves privacy of data owners and ensures secrecy for shared data with multiple service providers. It also provides auditing authorities with tamper-proof evidences for data usage compliance.