Owing to some special characteristics and features, blockchain is a very useful technique that can securely organize diverse devices in a smart city. It finds wide applications, especially in distributed environments, where entities such as wireless sensors need to be certain of the authenticity of the server. As contemporary blockchain techniques that address post-quantum concerns have not been designed, in this study, we investigate a blockchain in the post-quantum setting and seek to discover how it can resist attacks from quantum computing. In addition, traditional proof of work (PoW)-based consensus protocols such as Bitcoin cannot supply memory mining, and the transaction capacity of each block in a blockchain is limited and needs to be expanded. Thus, a new post-quantum proof of work (post-quantum PoW) consensus algorithm for security and privacy of smart city applications is proposed. It can be used to not only protect a blockchain under a quantum computing attack compared to existing classical hash-based PoW algorithms but also to supply memory mining. Meanwhile, an identity-based post-quantum signature is embedded into a transaction process to construct lightweight transactions. Subsequently, we provide a detailed description on the execution of the post-quantum lightweight transaction in a blockchain. Overall, this work can help enrich the research on future post-quantum blockchain and support the construction or architecture of emerging blockchain-based smart cities.
A detailed review on the technological aspects of Blockchain and Physical Unclonable Functions (PUFs) is presented in this article. It stipulates an emerging concept of Blockchain that integrates hardware security primitives via PUFs to solve bandwidth, integration, scalability, latency, and energy requirements for the Internet-of-Energy (IoE) systems. This hybrid approach, hereinafter termed as PUFChain, provides device and data provenance which records data origins, history of data generation and processing, and clone-proof device identification and authentication, thus possible to track the sources and reasons of any cyber attack. In addition to this, we review the key areas of design, development, and implementation, which will give us the insight on seamless integration with legacy IoE systems, reliability, cyber resilience, and future research challenges.
Open access
Physical Unclonable Functions (PUFs) and Hardware Security
Decentralized blockchain platforms have enabled the secure exchange of crypto-assets without the intermediation of trusted authorities. To this purpose, these platforms rely on a peer-to-peer network of byzantine nodes, which collaboratively maintain an append-only ledger of transactions, called blockchain. Transactions represent the actions required by users, e.g. the transfer of some units of crypto-currency to another user, or the execution of a smart contract which distributes crypto-assets according to its internal logic. Part of the nodes of the peer-to-peer network compete to append transactions to the blockchain. To do so, they group the transactions sent by users into blocks, and update their view of the blockchain state by executing these transactions in the chosen order. Once a block of transactions is appended to the blockchain, the other nodes validate it, re-executing the transactions in the same order. The serial execution of transactions does not take advantage of the multi-core architecture of modern processors, so contributing to limit the throughput. In this paper we develop a theory of transaction parallelism for blockchains, which is based on static analysis of transactions and smart contracts. We illustrate how blockchain nodes can use our theory to parallelize the execution of transactions. Initial experiments on Ethereum show that our technique can improve the performance of nodes.
Sina Rafati Niya, Benjamin Jeffrey, Burkhard Stiller
The integration of Internet-of-Things (IoT) and Blockchains (BC) for trusted and decentralized approaches enabled modern use cases, such as supply chain tracing, smart cities, and IoT data marketplaces. For these it is essential to identify reliably IoT devices, since the producer-consumer trust is not guaranteed by a Trusted Third Party (TTP). Therefore, this work proposes a Know Your IoT device platform (KYoT), which enables the self-sovereign identification of IoT devices on the Ethereum BC. KYoT permits manufacturers and device owners to register and verify IoT devices in a self-sovereign fashion, while data storage security is ensured. KYoT deploys an SRAM-based (Static Random Access Memory) Physically Unclonable Function (PUF), which takes advantage of the manufacturing variability of devices' SRAM chips to derive a unique identifying key for each IoT device. The self-sovereign identification mechanism introduced is based on the ERC 734 and ERC 735 Ethereum identity standards.
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Physical Unclonable Functions (PUFs) and Hardware Security
Maya Dotan, Yvonne-Anne Pignolet, Stefan Schmid, Saar Tochner · 5 authors
Cryptocurrencies such as Bitcoin are realized using distributed systems and hence critically rely on the performance and security of the interconnecting network. The requirements on these networks and their usage, however can differ significantly from traditional communication networks, with implications on all layers of the protocol stack. This paper is motivated by these differences, and in particular by the observation that many fundamental design aspects of these networks are not well-understood today. In order to support the networking community to contribute to this emerging application domain, we present a structured overview of the field, from topology and neighbor discovery to block and transaction propagation. In particular, we provide the context, highlighting differences and commonalities with traditional networks, review the state-of-the-art, and identify open research challenges. Our paper can hence also be seen as a call-to-arms to improve the foundation on top of which cryptocurrencies are built.
Jiejun Hu, Martin J. Reed, Nikolaos Thomos, Mays F. AI-Naday · 5 authors
The Internet of Things (IoT) connected by software-defined networking (SDN) promises to bring great benefits to cyber-physical systems. However, the increased attack surface offered by the growing number of connected vulnerable devices and separation of SDN control and data planes could overturn the huge benefits of such a system. This article addresses the vulnerability of the trust relationship between the control and data planes. To meet this aim, we propose an edge computing-based Blockchain as a Service (BaaS), enabled by an external BaaS provider. The proposed solution provides verification of inserted flows through an efficient, edge-distributed, blockchain solution. We study two scenarios for the blockchain reward purpose: 1) information symmetry, in which the SDN operator has direct knowledge of the real effort spent by the BaaS provider and 2) information asymmetry, in which the BaaS provider controls the exposure of information regarding spent effort. The latter yields the so-called “moral hazard,” where the BaaS may claim higher than actual effort. We develop a novel mathematical model of the edge BaaS solution and propose an innovative algorithm of a fair reward scheme based on game theory that takes into account moral hazard. We evaluate the viability of our solution through analytical simulations. The results demonstrate the ability of the proposed algorithm to maximize the joint profits of the BaaS and SDN operator, i.e., maximizing the social welfare.
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.
Open access
Physical Unclonable Functions (PUFs) and Hardware Security
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.
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.
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.
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.
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.
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.
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.
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.
Each of the most popular blockchain platform, Bitcoin, Ethereum, and Hyperledger Fabric, varies in aspects of decentralization, permission, anonymity, and native-currency, has its own consensus mechanism, algorithm and implementation. In the mainstream blockchain technology, there are many common consensus algorithms. They differ in terms of computational complexity, fault-tolerance, and resilience. The performance, consistency, scalability, and efficiency of blockchain consensus mechanism need further improvement and optimization. Consensus mechanism and code implementation of Bitcoin, Ethereum and Hyperledger are analyzed, discussed and proposed.
Pekka Nikander, Juuso Autiosalo, Santeri Paavolainen
The upsurge of Industrial Internet of Things is forcing industrial information systems to enable less hierarchical information flow. The connections between humans, devices, and their digital twins are growing in numbers, creating a need for new kind of security and trust solutions. To address these needs, industries are applying distributed ledger technologies, aka blockchains. A significant number of use cases have been studied in the sectors of logistics, energy markets, smart grid security, and food safety, with frequently reported benefits in transparency, reduced costs, and disintermediation. However, distributed ledger technologies have challenges with transaction throughput, latency, and resource requirements, which render the technology unusable in many cases, particularly with constrained Internet of Things devices.To overcome these challenges within the Industrial Internet of Things, we suggest a set of interledger approaches that enable trusted information exchange across different ledgers and constrained devices. With these approaches, the technically most suitable ledger technology can be selected for each use case while simultaneously enjoying the benefits of the most widespread ledger implementations. We present state of the art for distributed ledger technologies to support the use of interledger approaches in industrial settings.
Software-Defined Networking (SDN) separates the network control plane and data plane, which provides a network-wide view with centralized control (in the control plane) and programmable network configuration for data plane injected by SDN applications (in the application plane). With these features, a number of drawbacks of the traditional network architectures such as static configuration, non-scalability and low efficiency can be effectively avoided. However, SDN also brings with it some new security challenges, such as single-point failure of the control plane, malicious flows from applications, exposed network-wide resources and a vulnerable channel between the control plane and the data plane. In this paper, we design a monolithic security mechanism for SDN based on Blockchain. Our mechanism decentralizes the control plane to overcome single-point failure while maintaining a network-wide view. The mechanism also guarantees the authenticity, traceability, and accountability of application flows, and hence secures the programmable configuration. Moreover, the mechanism provides a fine-grained access control of network-wide resources and a secure controller-switch channel to further protect resources and communication in SDN.
Kun Wu, Guohao Dai, Xing Hu, Shuangchen Li · 7 authors
Blockchain applications have shown huge potential in various domains. Proof of Work (PoW) is the key procedure in blockchain applications, which exhibits the memory-bound characteristic and hinders the performance improvement of blockchain accelerators. In order to mitigate the "memory wall" and improve the performance of memory-hard PoW accelerators, using Ethash as an example, we optimize the memory architecture from two perspectives: 1) Hiding memory latency. We propose specialized context switch design to overcome the uncertain cycles of repetitive memory requests. 2) Increasing memory bandwidth utilization. We introduce on-chip memory that stores a portion of the Ethash directed acyclic graph (DAG) for larger effective memory bandwidth, and further propose adopting embedded NOR flash to fulfill the role. Then, we conduct extensive experiments to explore the design space of our optimized memory architecture for Ethash, including number of hash cores, on-chip/off-chip memory technologies and specifications. Based on the design space exploration, we finally provide the guidance for designing the memory-bound PoW accelerator. The experiment results show that our optimized designs achieve 8.7% -- 55% higher hash rate and 17% -- 120% higher hash rate per Joule compared with the baseline design in different configurations.
Globalization of IC supply chain has increased the risk of counterfeit, tampered, and re-packaged chips in the market. Counterfeit electronics poses a security risk in safety critical applications like avionics, SCADA systems, and defense. It also affects the reputation of legitimate suppliers and causes financial losses. Hence, it becomes necessary to develop traceability solutions to ensure the integrity of supply chain, from the time of fabrication to the end of product-life, which allows a customer to verify the provenance of a device or a system. In this article, we present an IC traceability solution based on blockchain. A blockchain is a public immutable database that maintains a continuously growing list of data records secured from tampering and revision. Over the lifetime of an IC, all ownership transfer information is recorded and archived in a blockchain. This safe, verifiable method prevents any party from altering or challenging the legitimacy of the information being exchanged. However, a chain of sales record is not enough to ensure provenance of an IC. There is a need for clone-proof method for securely binding the identity of an IC to the blockchain information. In this article, we propose a method of IC supply chain traceability via blockchain pegged to embedded physically unclonable function (PUF). The blockchain provides ownership transfer record, while the PUF provides unique identification for an IC allowing it to be linked uniquely to a blockchain. Our proposed solution automates hardware and software protocols using blockchain-powered Smart Contract that allows supply chain participants to authenticate, track, trace, analyze, and provision chips throughout their entire life cycle.
Open access
Physical Unclonable Functions (PUFs) and Hardware Security
Integrated Circuits and Semiconductor Failure Analysis
The widespread computer network has been changing drastically and substantially since blockchain and IoT entered the stage. Blockchain is good at protecting data transactions between logical nodes with a desirable guaranty. Internet of Things (IoT), on the other hand, by providing ultimate convenience to consumers, is expected to give rise to many various merits in a broad business scene. The security of IoT is still an open problem and if blockchain can reinforce IoT security, as many authors have hoped in recent papers, these newcomers appear to make a good collaboration to reinforce IoT security. However, software copes with logical nodes and IoT involves a vast number of physical nodes (IoT devices). Enabling blockchain to protect IoT cannot be brought to reality without respectively identifying logical and physical nodes. This is identical to the Proof-of-Trust problem. In this article, we propose a conceptual solution—Blockchained IoT—and show that this concept is able to be realized on-chip level using mass-produced dynamical random access memory (DRAM). We have completed the first test of longevity and temperature dependence (−40 °C to 105 °C) to confirm the necessary characteristics for the 5G base stations that are known to have an issue of self-heating. Furthermore, we have coarsely evaluated the probability of two DRAM IC chips being associated with an identical cyber-physical chip identification accidentally. Then, such a probability is minimal.
Open access
Physical Unclonable Functions (PUFs) and Hardware Security
Blockchain technology has become extremely popular, during the last decade, mainly due to the successful application in the cryptocurrency domain. Following the explosion of Bitcoin and other cryptocurrencies, blockchain solutions are being deployed in almost every aspect of transactional operations as a means to safely exchange digital assets between non-trusted parties. At the heart of every blockchain deployment is the consensus protocol, which maintains the consistency of the blockchain upon satisfying incoming transactions. Although many consensus protocols have been recently introduced, the most prevalent is Proof-of- Work, which scales the blockchain globally by converting the consensus problem to a competition based on cryptographic hash functions; a process called “mining”. The Proof-of- Work consensus protocol employs memory-hard algorithms in order to counteract ASIC or FPGA mining that may compromise the decentralization and democratization of the blockchain. Unfortunately, this leads to increased power consumption and scalability challenges since numerous processing units such as GPUs, FPGAs, and ASICs, are required to satisfy the ever-increasing operational requirements of blockchain deployments. In this paper, we perform an in-depth performance analysis and characterization of the most common memory-hard PoW algorithms running on NVIDIA GPUs. Motivated by our experimental findings, we apply a series of optimizations on Ethash algorithm, the consensus protocol of the Ethereum blockchain. The implemented optimizations accelerate performance by 14% and improve energy efficiency by 10% when executing on three NVIDIA GPUs. As a result, the optimized Ethash algorithm outperformed its fastest commercial implementation.
Provably neutral clouds are undoubtedly a viable solution to blockchain scaling. By optimizing the transport layer, not only can the throughput be fundamentally scaled up, but the latency could be dramatically reduced. Indeed, the latency distribution in today’s data centers is already biased toward microsecond timescales for most of the flows, with millisecond timescales residing only at the tail of the distribution. There is no reason why a BDN point of presence would not be able to achieve a similar performance. Adding dedicated optical infrastructure among such BDN points of presence would further alleviate throughput and reduce latency, creating the backbone of an advanced BDN. The key to this vision, however, lies in establishing trust by the blockchain ecosystem into the underlying networking infrastructure. This, in turn, is achieved by decoupling authority from infrastructure via a provably neutral network design.