Blockchain Papers

Raffaele Martino, Alessandro Cilardo

No abstract is available for this record.

Bertrand Cambou, Michael Gowanlock, Julie Heynssens, Saloni Jain · 10 authors

Blockchain technology is a game-changing, enhancing security for the supply chain of smart additive manufacturing. Blockchain enables the tracking and recording of the history of each transaction in a ledger stored in the cloud that cannot be altered, and when blockchain is combined with digital signatures, it verifies the identity of the participants with its non-repudiation capabilities. One of the weaknesses of blockchain is the difficulty of preventing malicious participants from gaining access to public–private key pairs. Groups of opponents often interact freely with the network, and this is a security concern when cloud-based methods manage the key pairs. Therefore, we are proposing end-to-end security schemes by both inserting tamper-resistant devices in the hardware of the peripheral devices and using ternary cryptography. The tamper-resistant devices, which are designed with nanomaterials, act as Physical Unclonable Functions to generate secret cryptographic keys. One-time use public–private key pairs are generated for each transaction. In addition, the cryptographic scheme incorporates a third logic state to mitigate man-in-the-middle attacks. The generation of these public–private key pairs is compatible with post quantum cryptography. The third scheme we are proposing is the use of noise injection techniques used with high-performance computing to increase the security of the system. We present prototypes to demonstrate the feasibility of these schemes and to quantify the relevant parameters. We conclude by presenting the value of blockchains to secure the logistics of additive manufacturing operations.

Jorge Peña Queralta, Tomi Westerlund

Mobile edge computing (MEC) and next-generation mobile networks are set to disrupt the way intelligent and autonomous systems are interconnected. This will have an effect on a wide range of domains, from the Internet of Things to autonomous mobile robots. The integration of such a variety of MEC services in a inherently distributed architecture requires a robust system for managing hardware resources, balancing the network load and securing the distributed applications. Blockchain technology has emerged a solution for managing MEC services, with consensus protocols and data integrity checks that enable transparent and efficient distributed decision-making. In addition to transparency, the benefits from a security point of view are evident. Nonetheless, blockchain technology faces significant challenges in terms of scalability. In this chapter, we review existing consensus protocols and scalability techniques in both well-established and next-generation blockchain architectures. From this, we evaluate the most suitable solutions for managing MEC services and discuss the benefits and drawbacks of the available alternatives.

Jia Luo, F. Richard Yu, Qianbin Chen, Lun Tang

Recently, software-defined Industrial Internet of Things (SDIIoT), the integration of software-defined networking (SDN) and Industrial Internet of Things (IIoT), has emerged. It is perceived as an effective way to manage IIoT dynamically. Aiming to improve scalability and flexibility of SDIIoT, multi-SDN has been applied to form a physically distributed control plane to handle the large amount of data generated by industrial devices. However, as the core of multi-SDN, reaching consensus among multiple SDN controllers is a thorny issue. To meet the required design principle, this paper proposes a blockchain-enabled distributed architecture with SDIIoT to synchronize local views between distinct SDN controllers and finally reach the consensus of global view. On the other hand, both the cryptographic operations of blockchain and the noncryptographic computational tasks have access to the same computational resource pool of mobile edge cloud (MEC). In order to simultaneously optimize the throughput of blockchain and the energy consumption caused by computing, we adaptively allocate computational resources and the block size by jointly considering the trust features of SDN controllers and the resource requirements of non-cryptographic operations. To implement the truly distributed manner of blockchain, we describe our problem as a partially observable Markov decision process (POMDP) and propose a novel deep recurrent Q-network (DRQN) approach to solve it. In the simulation results, we compare two different protocols of blockchain and show the effectiveness of our scheme in either of them.

Sudip Maitra, Venkata P. Yanambaka, Ahmed Abdelgawad, Deepak Puthal · 5 authors

Internet of Things (IoT) refers to the network of interconnected smart physical objects that collect and exchange information for enabling smart applications and services. IoT devices are often battery powered and lack computational resources and as a consequence, traditional measures of providing security is not feasible in IoT systems which leads to major security vulnerabilities. Blockchain technology has proven to be a secure medium of transaction in trustless public networks and has the potential to resolve the security vulnerabilities intrinsic to IoT systems. However, reaching consensus throughout a blockchain network is computationally demanding and requires large amount of energy. Moreover, typical transactions in blockchain based applications are slow, compounding the issues in adopting blockchain technology in IoT systems. In this work, a lightweight consensus algorithm called Proof-of-Authentication (PoAh), was implemented on resource-constrained IoT edge nodes and evaluated in terms of latency and energy consumption. The implemented consensus algorithm reduces latency in block validation to 29.35 ms and energy consumption to 44.31 mJ for each transaction, demonstrating promise and potential, to feasibly implement blockchain technology in IoT systems.

Ivan Homoliak, Larangeira, Mario, Peresini, Martin, Szalachowski, Pawel

Distributed ledger systems (i.e., blockchains) have received a lot of attention. They promise to enable mutually untrusted participants to execute transactions while providing the immutability of the data and censorship resistance. Although decentralized ledgers are a disruptive innovation, as of today, they suffer from scalability, privacy, or governance issues. Therefore, they are inapplicable for many important use cases, where interestingly, centralized ledger systems might gain adoption. Unfortunately, centralized ledgers have also drawbacks, e.g., a lack of efficient verifiability or a higher risk of censorship and equivocation. In this paper, we present AQUAREUM, a novel framework for centralized ledgers removing their main limitations. By a unique combination of a trusted execution environment (TEE) with a public blockchain, AQUAREUM provides publicly verifiable non-equivocating censorship-evident private and high-performance ledgers. AQUAREUM is integrated with a Turing-complete virtual machine (e.g., EVM), allowing arbitrary transaction processing logic, such as transfers or client-specified smart contracts. AQUAREUM is fully implemented and can process over 400 transactions per second on a commodity PC. Furthermore, we modeled AQUAREUM using the Universal Composability framework and proved its security.

Peter Robinson, Raghavendra Ramesh

The Layer 2 Atomic Cross-Blockchain Function Calls protocol allows composable programming across Ethereum blockchains. It allows for inter-contract and inter-blockchain function calls that are both synchronous and atomic: if one part fails, the whole call graph of function calls is rolled back. Existing atomic cross-blockchain function call protocols are Blockchain Layer 1 protocols, which require changes to the blockchain platform software to operate. Blockchain Layer 2 technologies such as the one described in this paper require no such changes. They operate on top of the infrastructure provided by the blockchain platform software. This paper introduces the protocol and a more scalable variant, provides an initial safety and liveness analysis, and presents the expected overhead of using this technology when compared to using multiple non-atomic single blockchain transactions. The overhead is analysed for three scenarios involving multiple blockchains: the Hotel and Train problem, Supply Chain with Provenance, and an Oracle. The protocol is shown to provide 93.8 or 186 cross-blockchain function calls per second for the Hotel and Train scenario when there are many travel agencies, for the standard and scalable variant of the protocol respectively, given the Ethereum client, Hyperledger Besu's performance of 375 tps, assuming a block period of one second, and assuming all transactions take the same amount of time to execute as the benchmark transactions.

Carlos A. Velasco, Ricardo Colomo‐Palacios, Ramon Cano

The neural distributed ledger so lution presented here adopts a ledger-of-ledgers approach to perform the interconnection of multiple ledgers. Beyond interledger operability, it also enables the development of custom blockchain-based solutions, providing controlled costs and scalability while retaining decentralization and security.

Seyed Mojtaba Hosseini Bamakan, Amirhossein Motavali, Alireza Babaei Bondarti

No abstract is available for this record.

Lakshmi Padmaja Maddali, Meena Singh Dilip Thakur, R. Vigneswaran, M A Rajan · 6 authors

Many enterprise (permissioned) blockchain applications demand low latency to commit their transactions on the ledger. One way to reduce latency is by reducing the number of peers required to execute/endorse a transaction in a secure and consistent way. However, by reducing the number of endorsements, blockchain network can be vulnerable to attacks such as collusion. In this paper, we introduce a novel scheme VeriBlock to overcome this problem. Our idea is to reduce the redundant execution of smart contracts without compromising on the security of the blockchain system by leveraging Verifiable Computing (VC) (which provides mathematically verifiable proof of execution) and Trusted Execution Environment (TEE) (which provides an attestation of the code executed) approaches. We also implemented these approaches to derive insights. In the proposed scheme, few nodes execute the smart contact logic and all the other nodes verify it. We propose two different models in the proposed scheme, 1. Endorser-Verify model, where the verification is done as part of transaction endorsement, and 2. Committer- Verify model, where the verification is done at the time of transaction commit. We have built Endorser-Verify model using Hyperledger Fabric blockchain platform, Pinocchio and Intel SGX as VC and TEE respectively and performance of the proposed scheme is analyzed by running bidding use case. Based on the results, we observe that the running time for VC based technique is in the order of magnitude two when compared with the naive implementation. On the other hand the performance of SGX is better than VC based approach.

Akash Suresh Patil, Rafik Hamza, Hongyang Yan, Alzubair Hassan · 5 authors

No abstract is available for this record.

Yong Wang, June Li, Siyu Zhao, Fajiang Yu

Blockchain is making headlines due to it promises to provide a decentralized, transparent, tamper-resistant, traceable and verifiable historical transaction records that can resist faults of any single node. According to the latest data from State of the Dapps, developers have currently released 3,717 Decentralized Applications (DApps), only three have an average of more than 10,000 daily active users. Most of the real-world DApps exercise little of their potential power. The key reason is that the current permissioned blockchain systems suffer from poor performance and lack of confidentiality. To address this issue, we present Hybridchain, a system that combines blockchain with Trusted Execution Environment (TEE). Hybridchain decouples computation from consensus and adopts hierarchical network to minimize the computational burden and latency of on-chain execution by performing most of the heavy-weight computation off-chain. Hybridchain leverages secure communication protocols to enable each participant to share transaction data in a secure way. To mitigate the small enclave memory restriction of TEE, Hybridchain extends the enclave memory that allows blockchain applications running in TEE to securely store transaction records to the whole key-value storage codes placed outside of TEE. Analysis and experiments of sealed-bid auction show that Hybridchain can support confidentiality-preserving along with high performance.

Keke Gai, Ziyue Hu, Liehuang Zhu, Ruili Wang · 5 authors

No abstract is available for this record.

Xiaowei Ding, Litai Ren, Zizhou Sang, Zijie Zhang · 6 authors

No abstract is available for this record.

Mahmudul Hassan Ashik, Mirza Mohd Shahriar Maswood, Abdullah G. Alharbi, Deep Medhi

Blockchain is a public ledger which is distributed in nature and has become highly popular. Bitcoin is the most successful application of it. The reason behind Bitcoin's success lies in its Consensus mechanism which ensures the security from any kind of attack. Because of this, no dishonest miner can affect the chain to manipulate it according to their wish. Also, the double spending problem does not occur and there is no need to trust a third party in this network. The most common consensus protocol in bitcoin technology is Proof-of-Work (PoW) which entirely depends on the computation power of miners. Because of this dependency, Application-specific Integrated Circuits (ASIC) is designed for bitcoin mining. Thereafter, it has become a threat to its decentralized nature and has been monopolizing the validation of new blocks. It is not possible to halt the production of ASIC-based devices even if it threatens the decentralized applications. So, different types of consensus protocols are proposed to nullify this threat whereas all of them have failed to fully nullify it. ASIC devices are costly, so only a few miners can afford it and monopolize over blockchain network. In our work, Filtered Proof-of-Work (FPoW) is proposed and its ASIC-resistivity has been evaluated to make it a future-proof ASIC-resistant consensus protocol.

Zijian Bao, Qinghao Wang, Wenbo Shi, Lei Wang · 6 authors

As a decentralized, public, and digital ledger technology in Peer-to-Peer network, blockchain has received much attention from various fields, including finance, healthcare, supply chain, etc. However, some challenges (e.g., scalability, privacy, and security issues) severely affects the wide adoption of blockchain technology. Recently, Intel software guard extensions (SGX), as new trusted computing technologies, have provided a new solution to the above challenges in the blockchain area. Although many studies have focused on using SGX technology to enhance their schemes in the blockchain areas, no comprehensive survey has systematically analyzed and delineated these studies. This article is the first to systematically discuss the application status of SGX in the blockchain area. In this article, we study the scheme designs, advantages, and disadvantages of the existing works using a six-layer hierarchical structure of the blockchain. We also summarize the functions of SGX and formally analyze the advantages and disadvantages of SGX. Finally, we review the remaining challenges and present a list of possible directions for future research.

Aiman A. AbuSamra, Ahmed Alghoul, Rajai Alhimdiat, Mohammed Alashqar

No abstract is available for this record.

Hoai Luan Pham, Thi Hong Tran, Tri Dung Phan, Vu Trung Duong Le · 6 authors

In the Bitcoin network, computing double SHA-256 values consumes most of the network energy. Therefore, reducing the power consumption and increasing the processing rate for the double SHA256 algorithm is currently an important research trend. In this paper, we propose a high-data-rate low-power hardware architecture named the compact message expander (CME) double SHA-256. The CME double SHA-256 architecture combines resource sharing and fully unrolled datapath technologies to achieve both a high data rate and low power consumption. Notably, the CME algorithm utilizes the double SHA-256 input data characteristics to further reduce the hardware cost and power consumption. A review of the literature shows that the CME algorithm eliminates at least 9.68% of the 32-bit XOR gates, 16.49% of the 32-bit adders, and 16.79% of the registers required to calculate double SHA-256. We synthesized and laid out the CME double SHA-256 using CMOS 0.18 μm technology. The hardware cost of the synthesized circuit is approximately 13.88% less than that of the conventional approach. The chip layout size is 5.9 mm×5.9 mm, and the correctness of the circuit was verified on a real hardware platform (ZCU 102). The throughput of the proposed architecture is 61.44 Gbps on an ASIC with Rohm 180nm CMOS standard cell library and 340 Gbps on a FinFET FPGA 16nm Zynq UltraScale+ MPSoC ZCU102.

Qian Wang, Zhiping Jia, Tianyu Wang, Zhaoyan Shen · 7 authors

Blockchain has gained a lot of attention from both academia and industry. However, traditional standard blockchains, such as Bitcoin and Ethereum, suffer from low throughput, high computation overhead, and large transaction fee, which is not suitable for Internet of Things (IoT) transactions. Recently, transaction-based approaches, such as Tangle structure which is based on a directed acyclic graph (DAG), have emerged to solve blockchain scalability issues for IoT environment. In transaction-based blockchain, for a transaction, namely, a node, to be attached to the Tangle, it needs to verify two other transactions. However, with the Tangle expanding, this attaching process consumes huge computational resources and energy, which severely limits the performance of the transaction-based blockchain. In this article, we present Re-Tangle, a highly parallelized processing-in-memory (PIM)-based accelerator for transaction-based blockchain. Re-Tangle is composed of a random walking module, a transaction validation module, and a PoW module, to improve the Tangle system performance. These modules transfer Tangle functions, such as fast exponentiation and modular, into ReRAM-based logic analog computation units. In the random walking module, Re-Tangle maintains an exponentiation table to reduce its design complexity and improve its computation efficiency. In the transaction validation module, Re-Tangle further proposes a highly parallel modular unit to accelerate the validation of different tags in a transaction. In the PoW module, we decompose the Curl hash function into basic logic OR, AND, SHIFT, and XOR operations, and map these logic operations to ReRAM crossbars in parallel to accelerate the working process. The experimental results show that Re-Tangle distinguishes itself from other architectures with significant performance improvement and energy saving. The throughput of Re-Tangle is about 22.4× and 2.38× higher compared with CPU and GPU, respectively, and the energy consumption of Re-Tangle is 83.5× and 5.77× less for equal workload.

Saraju P. Mohanty, Venkata P. Yanambaka, Elias Kougianos, Deepak Puthal

This is an extended abstract for the research demo of a novel hardware-assisted scalable blockchain called PUFChain. This work presents a scalable energy-efficient private/permissioned blockchain (integrated with Physical Unclonable Functions or PUFs) which can be deployed in the IoT. PUFs have a multiple of roles in the blockchain: higher security, lower latency, and reduced energy consumption. Experimental validations of PUFChain show a transaction time of 198ms. To the best of authors knowledge this is the first ever work that presents a comprehensive framework integrating PUFs in a blockchain.

Jorge Peña Queralta, Tomi Westerlund

One of the key challenges in the collaboration within heterogeneous multi-robot systems is the optimization of the amount and type of data to be shared between robots with different sensing capabilities and computational resources. In this paper, we present a novel approach to managing collaboration terms in heterogeneous multi-robot systems with blockchain technology. Leveraging the extensive research of consensus algorithms in the blockchain domain, we exploit key technologies in this field to be integrated for consensus in robotic systems. We propose the utilization of proof of work systems to have an online estimation of the available computational resources at different robots. Furthermore, we define smart contracts that integrate information about the environment from different robots in order to evaluate and rank the quality and accuracy of each of the robots' sensor data. This means that the key parameters involved in heterogeneous robotic collaboration are integrated within the Blockchain and estimated at all robots equally without explicitly sharing information about the robots' hardware or sensors. Trustability is based on the verification of data samples that are submitted to the blockchain within each data exchange transaction and validated by other robots operating in the same environment. Initial results are reported which show the viability of the concepts presented in this paper.

Qin Huang, Li Quan, Shengli Zhang

Blockchain is considered to be able to solve the problem of trust between distributed nodes. However, it's a challenge to store the large amount of data produced by blockchain. Therefore, it is necessary to reduce node storage overhead while ensuring node independence and data recoverability. This paper proposes to downsample these data to reduce the storage overhead of nodes. These nodes keep good independence, if downsampling follows the entropy of blockchain and the block bodies are continuously stored. Moreover, it demonstrates that the entire blockchain history can be efficiently recovered through the cooperative decoding of a group of nodes like fountain codes, if reserved data over these nodes obey the soliton distribution. However, these data on nodes are transparent (stored data are uncoded and can be used directly by the node without decoding). Thus, the proposed algorithm not only keeps decentralization and security, but also has good scalability in independence and recoverability.

Qian Wang, Tianyu Wang, Zhaoyan Shen, Zhiping Jia · 6 authors

Blockchain has gained a lot of attentions from both academic and industry. Transaction-based approaches such like Tangle structure, which is based on a DAG (Directed Acyclic Graph), are emerging to solve the blockchain scalability issues for IoT environment. In transaction-based blockchain, for a transaction, namely a node, to be attached to the Tangle, it needs to verify two other transactions. However, with the Tangle expanding, this attaching process consumes huge computational resources and energy, which severely limits the performance of the transaction-based blockchain. In this paper, we present Re-Tangle, a novel transaction-based blockchain acceleration architecture that explores the opportunity of performing massive parallel operations with low hardware and energy cost. Re-Tangle consists of a random walking module and a transaction validation module, which transfer Tangle functions into ReRAM-based logic analog computation units. In the random walking module, Re-Tangle maintains a exponentiation translator to reduce its design complexity and improve its computation efficiency for exponentiation. In the transaction validation module, Re-Tangle further proposes a highly parallel modular unit to accelerate the validation of different tags in a transaction. The experience results show that Re-Tangle distinguishes itself from other architectures, with significant performance improvement and energy saving. The throughput of Re-Tangle is about 19.4× and 2.13× higher compared with CPU and GPU, respectively, and the energy consumption of Re-Tangle is 63.35 × and 4.92 × less.

Gang Wang, Zhijie Shi, Mark Nixon, Song Han

Blockchain, a potentially disruptive technology, advances many different applications, e.g., crypto-currencies, supply chains, and the Internet of Things. Under the hood of blockchain, it is required to handle different kinds of digital assets and data. The next-generation blockchain ecosystem is expected to consist of numerous applications, and each application may have a distinct representation of digital assets. However, digital assets cannot be directly recorded on the blockchain, and a tokenization process is required to format these assets. Tokenization on blockchain will inevitably require a certain level of proper standards to enrich advanced functionalities and enhance interoperable capabilities for future applications. However, due to specific features of digital assets, it is hard to obtain a standard token form to represent all kinds of assets. For example, when considering fungibility, some assets are divisible and identical, commonly referred to as fungible assets. In contrast, others that are not fungible are widely referred to as non-fungible assets. When tokenizing these assets, we are required to follow different tokenization processes. The way to effectively tokenize assets is thus essential and expecting to confront various unprecedented challenges. This paper provides a systematic and comprehensive study of the current progress of tokenization on blockchain. First, we explore general principles and practical schemes to tokenize digital assets for blockchain and classify digitized tokens into three categories: fungible, non-fungible, and semi-fungible. We then focus on discussing the well-known Ethereum standards on non-fungible tokens. Finally, we discuss several critical challenges and some potential research directions to advance the research on exploring the tokenization process on the blockchain. To the best of our knowledge, this is the first systematic study for tokenization on blockchain.