Blockchain Papers

Aaliya Sarfaraz, Ripon K. Chakrabortty, Daryl Essam

No abstract is available for this record.

Ning Lu, Yuan Chang, Wenbo Shi, Kim‐Kwang Raymond Choo

Coin mixing can be used to preserve identity privacy of Bitcoin owners, by engaging a set of middlepersons (i.e.,$Mix$) to temporarily hold the transacting Bitcoins and remove the linkage between the transacting parties. However, existing schemes are generally not scalable due to limitations associated with the anonymity set and self-credibility. In this article, we propose an efficient coin mixing scheme (hereafter referred to as CoinLayering). To achieve strong anonymity, CoinLayering randomly selects two sets of middlepersons to respectively execute Bitcoin holding and Bitcoin trading. The seller can also select lower-loaded sets of middlepersons in the shortest time possible. We also design two coin mixing protocols, CoinLayering-PA and CoinLayering-PB, to mitigate the risk due to misbehaving middlepersons and$Supervisor$. We then mathematically prove that CoinLayering achieves both strong anonymity and self-credibility, and evaluate its performance to demonstrate its scalability.

Diego Fernandes Gonçalves Martins, Marco Aurélio Amaral Henriques

Este artigo apresenta o protocolo de consenso Probabilistic Proof-of-Stake (PPoS) e analisa o mesmo dos pontos de vista teórico e prático, focando na sua probabilidade de produzir forks. O texto primeiramente explica o funcionamento do algoritmo, onde é possível entender como um nó participa de um sorteio em rodadas a fim de ganhar o direito de criar um novo bloco para uma cadeia. Em seguida ele apresenta os critérios para aceitação e para confirmação de blocos, seguidos de uma análise da probabilidade de forks e do número esperado de rodadas entre dois blocos consecutivos. Uma blockchain baseada neste protocolo foi implementada e seus resultados práticos mostraram uma boa concordância com a análise teórica, validando a mesma.

Wenyue Sun, Haokun Fang, Shensheng Zheng, Quan Qian

Internet, especially mobile Internet, brings a new channel for digital content distribution. However, all the new technology can make users easily share, modify and redistribute the digital contents out of the owner's control, which have created new intellectual property issues. In this paper, we use blockchain and homomorphic encryption to implement a detailed copyright auction system, which not only can protect the digital contents copyright from the view of the contents owner, but also from the privacy and data security from the end clients. For homomorphic encryption, different algorithms are compared from the performance of key generation, encryption and decryption. Moreover, the security proof and statement of the whole procedure are also discussed in detailed in the paper.

Baowei Wang, Shi Jiawei, Weishen Wang, Peng Zhao

In the traditional image copyright protection system, watermarking technology is considered as an important technology to overcome the data protection problem and verify the data ownership relationship. However, the existing watermarking technology often needs a trusted third party to arbitrate in the implementation process, which may be difficult to find or costly. Meanwhile, the common image watermarking algorithm needs to operate the image data, which will inevitably lead to the image data loss. With the development of blockchain technology, the functions of de-trusted third parties and the fair and automatic processing characteristics of smart contracts attached to it have entered the public view. In this paper, we study the function of the zero-watermarking algorithm in image protection and its complete storage and authentication scheme, then propose a secure blockchain-based image copyright protection framework and build a system according to this framework. This framework combines blockchain and zero-watermark technology and uses interplanetary file system to solve the blockchain data expansion problem. Besides, the image owner can authenticate the image and realize the copyright traceability of the image. Furthermore, the keyword search function of the stored images in the system is realized based on a smart contract, which solves the problem of lack of trusted third parties. Experiment illustrates that the proposed scheme is feasible.

Wenti Yang, Zhitao Guan, Longfei Wu, Xiaojiang Du · 6 authors

With the development of information and communication technologies in smart grid, peer-to-peer (P2P) energy trading for distributed energy resources (DER) has achieved an efficient two-way flow of information and power. The adoption of blockchain technology makes the P2P energy trading more secure and transparent. Considering that users with extra energy may be reluctant to participate in the energy trading due to privacy concerns, many researchers have focused on potential privacy issues. However, most of the existing works are built on top of a semi-decentralized energy blockchain in which only a few certified third-party nodes are authorized to manage and verify transactions - once these authorized nodes are attacked, the system will be threatened. In this paper, we use the Ciphertext Policy Attribute-Based Encryption (CP-ABE) scheme to establish a blockchain based P2P energy trading approach with privacy preservation, which allows peer nodes, including sellers and purchasers, to manage and verify transactions autonomously without needing any additional third-party nodes. In addition, we introduce the redactable blockchain technology into our scheme to ensure users can modify their sensitive information uploaded to the blockchain. Furthermore, we improve the CP-ABE scheme to provide low latency in the system. The experimental evaluations show that our scheme is efficient and practical.

Israa Alsarsour, Qutaibah Malluhi, Yongge Wang

Everyone should have the right to expression and opinion without interference. Nevertheless, Internet censorship is often misused to block freedom of speech. The distributed ledger technology provides a globally shared database that is geographically distributed and that cannot be controlled by a central authority. Blockchain is an emerging technology that enabled distributed ledgers and has recently been employed for building various types of applications. This paper demonstrates a unique application of blockchain technologies to create a platform that supports the freedom of expression. The paper adapts permissionless and public blockchains in order to leverage their advantages of providing an immutable and tamper-proof digital ledger. The study shows the blockchain potential for providing censorship-resistant publication platform. The paper presents and evaluates possible methods for building such system using the Bitcoin and Ethereum blockchain networks. Our results demonstrate that the Ethereum blockchain is much more beneficial for our system as it requires much lower cost than Bitcoin. to use as a platform to allow freedom of speech.

Sven-Jannik Wöhnert, Kai Hendrik Wöhnert, Eldar Almamedov, Volker Skwarek

Proof of integrity in produced video data by surveillance cameras requires active forensic methods such as signatures, otherwise authenticity and integrity can be comprised and data becomes unusable e. g. for legal evidence. But a simple file- or stream-signature loses its validity when the stream is cut in parts or by separating data and signature. Using the principles of security in distributed systems similar to those of blockchain and distributed ledger technologies (BC/DLT), a chain which consists of the frames of a video which frame hash values will be distributed among a camera sensor network is presented. The backbone of this Framechain within the camera sensor network will be a camera identity concept to ensure accountability, integrity and authenticity according to the extended CIA triad security concept. Modularity by secure sequences, autarky in proof and robustness against natural modulation of data are the key parameters of this new approach. It allows the standalone data and even parts of it to be used as hard evidence.

Hossein Rezaeighaleh, Cliff C. Zou

Bitcoin and other altcoin cryptocurrencies use the Elliptic-Curve cryptography to control the ownership of coins. A user has one or more private keys to sign a transaction and send coins to others. The user locks her private keys with a password and stores them on a piece of software or a hardware wallet to protect them. A challenge in cryptocurrencies is losing access to private keys by its user, resulting in inaccessible coins. These coins are assigned to addresses which access to their private keys is impossible. Today, about 20 percent of all possible bitcoins are inaccessible and lost forever. A promising solution is the off-chain recovery transaction that aggregates all available coins to send them to an address when the private key is not accessible. Unfortunately, this recovery transaction must be regenerated after all sends and receives, and it is time-consuming to generate on hardware wallets. In this paper, we propose a new mechanism called lean recovery transaction to tackle this problem. We make a change in wallet key management to generate the recovery transaction as less frequently as possible. In our design, the wallet generates a lean recovery transaction only when needed and provides better performance, especially for micropayment. We evaluate the regular recovery transaction on two real hardware wallets and implement our proposed mechanism on a hardware wallet. We achieve a %40 percentage of less processing time for generating payment transactions with few numbers of inputs. The performance difference becomes even more significant, with a larger number of inputs.

M. V. Ranjith Kumar, N. Bhalaji

No abstract is available for this record.

Hoàng Việt Long, Tong Anh Tuan

Launched in 2008, blockchain technology with a typical product of Bitcoin is being applied and has great development potential in many areas such as finance, trade, manufacturing, and telecommunications. Bitcoin as a popular cryptocurrency with the highest total market capitalization of the virtual money market has always been an attractive target for hackers. In this chapter, we focus on attack and security on blockchain technology. In the first section, some targeted attacks on Bitcoins will be repeated. In the next section, we present potential attack techniques on blockchain technology in general and Bitcoin in particular, such as double-spending attack technique on mining pool or Bitcoin network. The general security solutions for block-chain will be presented in the next section. Besides, we devote a section to presenting the issue of how to secure wallets and Bitcoin transactions for those who use this virtual currency. The summary and discussion of future security orientation for blockchain technology will be presented at the end of the chapter.

Haotian Cao, Hao Yin, Feng Gao, Zijian Zhang · 7 authors

The quality of covert communications is determined by the choice of communication channels and the design of data embedding schemes. Recently, the Bitcoin system is prevalent as a covert communication channel. The consensus mechanism requires participants to spread their found valid blocks under an adjustable difficulty, which provides a stable periodic broadcast channel. Moreover, senders and receivers are difficult to be traced, because the Bitcoin system is pseudonymous. However, since the historical data in the ledger cannot be removed from the Bitcoin system, the openness and the persistent storage of the ledger in the Bitcoin system post new challenges when designing data embedding schemes. More concreteness, most traditional data embedding schemes either design by heuristic or empirical algorithms or use a fixed field to embed data in the transactions. Therefore, the covert data can be recognized once the algorithm is leaked or the pattern is explored. In this article, we first propose a hash chain-based covert data embedding (HC-CDE) scheme. The embedded transactions are difficult to be discovered. We further propose an elliptic curve Diffie–Hellman chain-based covert data embedding (ECDHC-CDE) scheme to enhance the security of the HC-CDE scheme. Experimental analysis on the Bitcoin Testnet verifies the security and the efficiency of the proposed schemes.

Lei Ding, Shida Wang, Renzhuo Wan, Guopeng Zhou

The privacy protection and information security are two crucial issues for future advanced artificial intelligence devices, especially for cooperative system with rich core data exchange which may offer opportunities for attackers to fake interaction messages. To combat such threat, great efforts have been made by introducing trust mechanism in initiative or passive way. Furthermore, blockchain and distributed ledger technology provide a decentralized and peer-to-peer network, which has great potential application for multi-agent system, such as IoTs and robots. It eliminates third-party interference and data in the blockchain are stored in an encrypted way permanently and anti-destroys. In this paper, a methodology of blockchain is proposed and designed for advanced cooperative system with artificial intelligence to protect privacy and sensitive data exchange between multi-agents. The validation procedure is performed in laboratory by a three-level computing networks of Raspberry Pi 3B+, NVIDIA Jetson Tx2 and local computing server for a robot system with four manipulators and four binocular cameras in peer computing nodes by Go language.

Weizheng Wang, Huakun Huang, Lejun Zhang, Chunhua Su

With the development of smart grid technology, The relationships between utility providers and their customers over electricity use have increased. Nonetheless, because the readings are performed through the Internet, there is a likelihood that the information will be conceded if it enters into the indicators of the wrong individuals. Furthermore, because they do not have access to the readings, consumers sometimes do not understand why they pay exorbitant fees or which gadgets consume the most power. In this article, To eliminate challenges, the autonomous blockchain technology that enables accountability and attribution, is deployed. A smart contract is also created, which performs preset tasks in order to build a trust-based mechanism among network participants. Our method is extremely efficient since the user can see how the electricity is used. The proposed smart contracts are extensively explained, and they comprise energy injection into smart networks, energy bidding to submit energy demand, energy trading, and energy use. It dynamically assigns weights to each predictor based on forecasting efficacy for the final judgement on predicting the outcome of these forecasters. Even in the presence of highly changing and ambiguous load patterns, the proposed model remains valid robust and accurate.

Abba Garba, Ashutosh Dhar Dwivedi, Mohsin Kamal, Gautam Srivastava · 7 authors

No abstract is available for this record.

Lejun Zhang, Zhijie Zhang, Zilong Jin, Yansen Su · 5 authors

The traditional covert communication that relies on a central node is vulnerable to detection and attack. Applying blockchain to covert communication can improve the channel's anti-interference and antitampering. Whisper is the communication protocol of Ethereum, which mainly relies on payload to store information and padding to expand. These two fields can store a large amount of information, creating conditions for the realization of covert communication. In this paper, we propose a covert communication method based on the whisper protocol to covertly transfer information in the blockchain. To implement this method, we use payload to store the carrier information, matching it with the secret message. The generated index is recorded in the padding field. To improve the concealment of communication, we simulate the default filling rules of the protocol to maintain the message size. A new topic–key pair interaction method is also proposed to improve the security of the model. Moreover, the anti-interference, antitampering and antidetection of the newly proposed model are verified through theoretical analysis and experiment. The experimental findings show that the amount of information in the proposed method is 4.7 times that of the traditional time-based covert communication. The time consumption of information transmission is reduced to 52.25% under the same settings and even less in actual use. The cost of the new topic–key pair interaction is reduced by nearly 50% compared with the original method.

Jiang Xiaomeng, Zhang Fan, Shenwen Lin, Yang Jinglin · 5 authors

With the development of the world economy and network technology, the security and anonymity of the Bitcoin blockchain are increasingly valued by people. At the same time, because Bitcoin does not have a unified regulatory agency, the Bitcoin blockchain has also brought a series of problems, such as drug transactions and online money laundering. Therefore, node information in the Bitcoin blockchain network needs to be collected and analyzed. Problematic transactions should be analyzed and the source should be traced accurately. This article mainly explains the basic technical principles and data structure of the Bitcoin blockchain, and summarizes the latest research on the data analysis of the Bitcoin blockchain network nodes in recent years. At the same time, relevant data for the last 100,000 blocks in the Bitcoin blockchain are collected and the recent changes in the data of the Bitcoin blockchain network nodes are showed in preparation for further analysis. Finally, the analysis of node data of the Bitcoin blockchain network is summarized and prospected.

Debashis Das, Sourav Banerjee, Utpal Biswas

No abstract is available for this record.

Franco Frattolillo

Digital watermarking can be used to implement mechanisms aimed at protecting the copyright of digital content distributed on the Internet. Such mechanisms support copyright identification and content tracking by enabling content providers to embed perceptually invisible watermarks into the distributed copies of content. They are employed in conjunction with watermarking protocols, which define the schemes of the web transactions by which buyers can securely purchase protected digital content distributed by content providers. In this regard, the “buyer friendly” and “mediated” watermarking protocols can ensure both a correct content protection and an easy participation of buyers in the transactions by which to purchase the distributed content. They represent a valid alternative to the classic “buyer and seller” watermarking protocols documented in the literature. However, their protection schemes could be further improved and simplified. This paper presents a new watermarking protocol able to combine the “buyer friendly” and “mediated” design approach with the blockchain technology. The result is a secure protocol that can support a limited and balanced participation of both buyers and content providers in the purchase transactions of protected digital content. Moreover, the protocol can avoid the direct involvement of trusted third parties in the purchase transactions. This can reduce the actual risk that buyers or sellers can violate the protocol by illicitly interacting with trusted third parties. In fact, such peculiarities make the proposed protocol suited for the current web context.

Kazumasa Omote, Asuka Suzuki, Teppei Sato

Trust of user address (i.e., wallet address) in Bitcoin is dependent on not who user is but the amount of Bitcoin currency in user's wallet address. So we cannot necessarily trust a Bitcoin user with wallet address. Actually, there is no method for assigning trust to user addresses in Bitcoin. Although we can provide trust to user address by inserting certificate into Bitcoin transaction using OP_RETURN, it still has some problems about wastefulness. In this paper, we propose a new method that efficiently assigns trust to user address using Bitcoin transfer only, which does not need to use OP_RETURN. Our proposed method can realize a trust providing mechanism for “Blockchain 1.0” without adding any new function. Main idea of our method is that “token coin” (Bitcoin transfer itself) can be used as a trust providing mechanism. For feasibility study, we experimentally show the trust assigning in the Bitcoin testnet. Furthermore, our method can be easily adopted into other cryptocurrencies.

Nisreen T. Hussein, Ali H. Kashmar

Abstract Blockchain technology has already changed industry and commercial enterprises remarkably. It is the underlying mechanism of a very well-known cryptocurrencies such as Bitcoin and Ethereum, and many other business applications. Therefore, its security draws the researchers’ attention more and more recently. One of Blockchain vulnerabilities is caused by weak randomness in ECDSA. A random number is not secure, cryptographically, which leads to a leakage in private key and even the user’s fund theft. As well the spam transaction attack may exploit the ECDSA weak randomness. This problem in security has been well known in cryptocurrencies community such as Bitcoin and fixed by applying RFC 6979 update in 2013. However, the problem is not entirely solved. The elliptic curve digital signature algorithm (ECDSA) was the first successful algorithm based on elliptic curve. This algorithm security depends on complexity of elliptic curve discrete logarithm problem (ECDLP). This algorithm applied in blockchain mechanism as a result of its low computational cost and short key. In this paper, we analyze the ECDSA weakness in blockchain and enhance its scheme by generating the signature with two secret keys. Using two secret keys will reduce the risk probability of revealing the secret key by knowing two messages. Therefore, the improved scheme can improve the security of the ECDSA.

魁 大月, Kai Ootuki, 遼平 坂野, Ryohei Banno · 6 authors

Bitcoin's throughput is far lower than those of centralized systems such as Visa and PayPal. To handle a comparable number of transactions, Bitcoin's throughput must be improved, which will require a reduction in the block propagation time. Relay networks have attracted attention as a method to improve throughput. However, the nature and strength of the effects of relay networks are not yet clear. In particular, the effects on individual nodes have received little attention. Thus, this study aims to investigate the effects of relay networks on the Bitcoin network and its nodes under the current network state in approximately 2019. We simulate a relay network under the current network state because simulation is virtually the only way to obtain data for all nodes. A major contribution of this study is that it is the first to investigate the relay network effect on the 90th percentile of block propagation time. Moreover, this study shows that relay networks benefit not only the system but also the nodes utilizing them. The utilizing nodes' blocks were more than six times more likely to be approved as valid blocks when nonutilizing and utilizing nodes generated blocks simultaneously. This finding can motivate the use of nodes in relay networks.

Binbing Hou, Chen Feng

Bitcoin is the world's first blockchain-based, peer-to-peer cryptocurrency system. Being tremendously successful, the Bitcoin system is designed to support reliable, secure, and trusted transactions between untrusted peers. Since its release in 2009, the Bitcoin system has rapidly grown to an unprecedentedly large scale. However, the real-world behaviors of miners and users in the system and the efficacy of the original Bitcoin system design in the field deployment still remain unclear, hindering us from understanding its internals and developing the next-generation cryptocurrency system. In this paper, we study the behaviors of Bitcoin miners and users and their interactions based on quantitative analysis of more than nine years of Bitcoin transaction history, from its first release on January 3rd, 2009 to April 30th, 2018. We have analyzed over 300 million transaction records to study the transactions' processing, confirmation, and implementation. We have obtained several critical findings regarding how the miners and users exploit the high degree of freedom provided by the Bitcoin system to achieve their own interests. For example, we find that miners often attempt to maximize their profits even by sacrificing system performance; users could try to speed up the transaction processing by mistakenly trading off security for reduced latency. Such unexpected behaviors, to some degree, deviate from the original design purposes of the Bitcoin system and could bring undesirable consequences. Besides revealing several unexpected behaviors of the Bitcoin miners and users in the real world, we have also discussed the associated system implications as well as optimization opportunities in the future.

Foteini Toutara, Γεώργιος Σπαθούλας

Biometric authentication is the preferred authentication scheme in modern computing systems. While it offers enhanced usability, it also requires cautious handling of sensitive users' biometric templates. In this paper, a distributed scheme that eliminates the requirement for a central node that holds users' biometric templates is presented. This is replaced by an Ethereum/IPFS combination to which the templates of the users are stored in a homomorphically encrypted form. The scheme enables the biometric authentication of the users by any third party service, while the actual biometric templates of the user never leave his device in non encrypted form. Secure authentication of users in enabled, while sensitive biometric data are not exposed to anyone. Experiments show that the scheme can be applied as an authentication mechanism with minimal time overhead.