Blockchain Papers

Thach Ngoc Nguyen, Olga Kosheleva, Владик Крейнович, Hoang Phuong Nguyen

No abstract is available for this record.

Elvira Albert, Pablo Gordillo, Albert Rubio, Ilya Sergey

Gas is a measurement unit of the computational effort that it will take to execute every single operation that takes part in the Ethereum blockchain platform. Each instruction executed by the Ethereum Virtual Machine (EVM) has an associated gas consumption specified by Ethereum. If a transaction exceeds the amount of gas allotted by the user (known as gas limit), an out-of-gas exception is raised. There is a wide family of contract vulnerabilities due to out-of-gas behaviours. We report on the design and implementation of GASTAP, a Gas-Aware Smart contracT Analysis Platform, which takes as input a smart contract (either in EVM, disassembled EVM, or in Solidity source code) and automatically infers sound gas upper bounds for all its public functions. Our bounds ensure that if the gas limit paid by the user is higher than our inferred gas bounds, the contract is free of out-of-gas vulnerabilities.

Nick Arnosti, S. Matthew Weinberg

Although Bitcoin was intended to be a decentralized digital currency, in practice, mining power is quite concentrated. This fact is a persistent source of concern for the Bitcoin community. We provide an explanation using a simple model to capture miners' incentives to invest in equipment. In our model, $n$ miners compete for a prize of fixed size. Each miner chooses an investment $q_i$, incurring cost $c_i q_i$, and then receives reward $\frac{q_i^α}{\sum_j q_j^α}$, for some $α\geq 1$. When $c_i = c_j$ for all $i,j$, and $α= 1$, there is a unique equilibrium where all miners invest equally. However, we prove that under seemingly mild deviations from this model, equilibrium outcomes become drastically more centralized. In particular, (a) When costs are asymmetric, if miner $i$ chooses to invest, then miner $j$ has market share at least $1-\frac{c_j}{c_i}$. That is, if miner $j$ has costs that are (e.g.) $20\%$ lower than those of miner $i$, then miner $j$ must control at least $20\%$ of the \emph{total} mining power. (b) In the presence of economies of scale ($α> 1$), every market participant has a market share of at least $1-\frac{1}α$, implying that the market features at most $\fracα{α- 1}$ miners in total. We discuss the implications of our results for the future design of cryptocurrencies. In particular, our work further motivates the study of protocols that minimize "orphaned" blocks, proof-of-stake protocols, and incentive compatible protocols.

Seep Goel, Abhishek Singh, Rachit Garg, Mudit Verma · 5 authors

In this paper, we consider the problem of fair scheduling of transactions of multiple types that are submitted to a permissioned blockchain system. Permissioned blockchains are being increasingly used for enterprise applications and by design are heterogeneous in nature, with different peer organizations performing different business functions. Transactions execute different smart contract operations that may have widely varying business importance. In such a setting, we argue that the typically adopted First-In-First-Out ordering mechanism for transactions in a blockchain system, which is a performance-limited resource, is inefficient and unfair. We propose a weighted fair queueing strategy for ordering transactions that can support differentiated quality of service for submitted transactions on the blockchain. The main challenge we address in this paper is to support fair allocation and differentiation in a decentralized manner, as there is no single authority that can facilitate this as in traditional systems. We demonstrate such a fair scheduling strategy and support multiple transaction types with different priorities on Hyperledger Fabric.

Christian Berger, Hans P. Reiser

Blockchains and distributed ledger technology (DLT) that rely on Proof-of-Work (PoW) typically show limited performance. Several recent approaches incorporate Byzantine fault-tolerant (BFT) consensus protocols in their DLT design as Byzantine consensus allows for increased performance and energy efficiency, as well as it offers proven liveness and safety properties. While there has been a broad variety of research on BFT consensus protocols over the last decades, those protocols were originally not intended to scale for a large number of nodes. Thus, the quest for scalable BFT consensus was initiated with the emerging research interest in DLT. In this paper, we first provide a broad analysis of various optimization techniques and approaches used in recent protocols to scale Byzantine consensus for large environments such as BFT blockchain infrastructures. We then present an overview of both efforts and assumptions made by existing protocols and compare their solutions.

Zsolt István, Alessandro Sorniotti, Marko Vukolić

Processing at block granularity and blockchains seem inseparable. The original role of blocks is to amortize the cost of cryptography (e.g., solving proof-of-work) and to make data transfers more efficient in a geo-distributed setting. While blocks are a simple and powerful tool for amortizing these costs, today in permissioned distributed ledgers, that are often neither geo-distributed, nor require proof-of-work, the benefits of operating on blocks are overshadowed by the large latencies they introduce.

Daniel Sel, Kaiwen Zhang, Hans‐Arno Jacobsen

The success and growing popularity of blockchain technology has lead to a significant increase in load on popular permissionless blockchains such as Ethereum. With the current design, these blockchain systems do not scale with additional nodes since every node executes every transaction. Further efforts are therefore necessary to develop scalable permissionless blockchain systems.

Astitva Narayan Pandey, Himanshu Gupta

No abstract is available for this record.

Jollen Chen

This paper addresses the issue of secure and trusted Internet of Things (IoT) networks by adopting the emerging blockchain technologies. This paper proposes a new hybrid blockchain technology to address the trusted IoT issues such as trustless communications and decentralized applications. Besides, we also present that the pseudonymous authentication technique can use a puzzle-solving computation to enable trustless communications for the IoT and provide the capabilities of near real-time transactions. In our previous work, we presented a decentralized software framework for the IoT by using a p2p network and the concept of the blockchain. In this paper, we outline the core components of the hybrid blockchain and delve deeper the algorithms of the hybrid consensus to provide the capabilities for our hybrid blockchain technology.

Xinxin Fan, Qi Chai

Delegated Proof-of-Stake (DPoS) is an efficient, decentralized, and flexible consensus framework available in the blockchain industry. However, applying DPoS to the decentralized Internet of Things (IoT) applications is quite challenging due to the nature of IoT systems such as large-scale deployments and huge amount of data. To address the unique challenge for IoT based blockchain applications, we present Roll-DPoS, a randomized delegated proof of stake algorithm. Roll-DPoS inherits all the advantages of the original DPoS consensus framework and further enhances its capability in terms of decentralization as well as extensibility to complex blockchain architectures. A number of modern cryptographic techniques have been utilized to optimize the consensus process with respect to the computational and communication overhead.

Subhra Mazumdar, Sushmita Ruj

Permissioned Blockchain has become quite popular with enterprises forming consortium since it prioritizes trust over privacy. One of the popular platforms for distributed ledger solution,Hyperledger Fabric, requires a transaction to beendorsedor approved by a group of special members known as endorsers before undergoing validation. To endorse a transaction, an endorser mentions its identity along with the signature so that it can be verified later. However, for certain transactions, difference in opinion may exist among endorsers. Disclosing the identity of an endorser may lead to conflict within the consortium. In such cases, an endorsement policy which not only allows an endorser to support a transaction discreetly, but at the same time takes into account the decision of the majority is preferred. Thus we propose an Anonymous Endorsement System which uses a threshold endorsement policy in order to address the issue. To realize at-out-of-nendorsement policy, using any of the existing threshold ring signature for our endorsement system would have violated the privacy of endorsers as either the identity or the secret key of the endorsers get revealed to the party who recombines the signature after collecting each signature share. All these factors motivated us to design a new ring signature scheme, calledFabric’s Constant-Sized Linkable Ring Signature(FCsLRS) withTransaction-Orientedlinkability for hiding identity of the endorsers. We have implemented the signature scheme in Golang and analyzed its security and performance by varying the Rivest-Shamir-Adleman (RSA) modulus size. Feasibility of implementation is supported by experimental analysis. Signature and tag generation time is quite fast and remains constant irrespective of change in message length or endorsement set size for a given RSA modulus value, assuming all the endorsers generates their signature in parallel. Each verifier is required to count and check individual valid ring signature. If the aggregate is above the threshold value, stated by the endorsement policy, then it confirms that the transaction is valid. This increases the verification time depending on the threshold value, but has very little effect on the scalability since generally$t<\!\!\!<n$. Lastly, we also discuss the integration of the scheme on v1.2 Hyperledger Fabric.

Jean‐Philippe Martin, Eunjin, Jung

Blockchain systems benefit from lessons in prior art such as fault tolerance, distributed systems, peer-to-peer systems, and game theory. In this paper we argue that blockchain algorithms should tolerate both rational (self-interested) users and Byzantine (malicious) ones, rather than assuming all non-Byzantine users are altruistic and follow the protocols blindly. Such algorithms are called BAR-tolerant [1]. To design a BAR-tolerant system, one can follow these three steps: clearly define the utility function for the rational users, prove the algorithm is such that there is no benefit from unilaterally deviating (that is, it's a Byzantine Nash Equilibrium), then prove the algorithm correct assuming the rational actors follow the protocol. We present an example attack by rational users: the gatekeeping attack, where members of a system selfishly decide to prevent newcomers from joining. This attack may affect any stake-based system where the existing members prevent newcomers from making a stake, and essentially form a cartel. We then sketch a BAR-tolerant consensus protocol for blockchain that can defend against this attack. It relies on a strict order to decide who gets to propose a new block (so there's no need to race to solve a crypto puzzle) and it relies on hardware ID tokens to make sure every computer is only represented at most once as a block proposer to mitigate Sybil attacks. It also defends against the gatekeeper attack. The BAR-tolerant approach is naturally also applicable to other blockchain algorithms.

Mason J. Molesky, Elizabeth A. Cameron, Jerry Jones, Michael Esposito · 6 authors

This paper proposes a solution to facilitate on-orbit satellite communication data integrity and security by utilizing blockchain technology. A proliferating demand has created a growing reliance on satellites for communications, GPS, imagery, and other uses. The decreased cost of entry into the space industry has increased the number of entrants and also the number of satellites and the amount of space debris. These orbital debris pose a serious threat to spacecraft. Therefore, tracking these objects is crucial. Blockchain technology offers a unique solution to this problem by utilizing functions, processes, and information already incorporated into satellites while maintaining a maximum of forty-eight hours of data. The use of blockchain provides a high level of trusted positional data that can be used to predict and avoid collisions which will save billions of dollars and valuable time. This paper provides a technological design, rational, and risk analysis of this proposal.

Yuli Meng, Zhao Cao, Dacheng Qu

With the great success of Bitcoin, the blockchain, as its key underlying technology, has been paid more and more concern. However, the Proof-of-Work (PoW) mechanism used by Bitcoin requires long confirmation time and wastes more computing resource. Practical Byzantine Fault Tolerance (PBFT), as another important protocol that has been widely used, which can tolerate at most 1/3 corruptions, meanwhile confirm transactions with quick speed. In fact, it is difficult to implement and maintain it with a large-scale setting. In this paper, considering a permissioned setting, we propose a Byzantine protocol based on the committee, and elect a committee to reach the consensus on behalf of all participants. In steady state, our protocol uses PBFT to approve transactions among all members of the committee. In election state, we use an efficient election algorithm which can combine the latest consensus results with the participants' authentication information to elect a new committee. Our protocol improves on Bitcoin in confirmation time and provides safety and liveness on the condition of the amount of Byzantine participants are less than 1/3.

Sorin Zoican, Marius Vochin, Roxana Zoican, Dan Galațchi

this paper focuses on the performance evaluation of consensus algorithms used in a blockchain system for Internet of Things (IoT). In such systems the time necessary to achieve consensus should be small. Three most used consensus algorithms (modified proof of work, practical byzantine fault tolerance and binary consensus) are evaluated in different situations – type of motes, number of nodes participating in consensus algorithm and radio propagation model. An integrated solution is proposed to adapt an IoT node to different consensus algorithm. The simulations in Contiki IoT operating system show good performance (time to achieve consensus less than seconds)

Zhancang Wang

In recent years, with Bitcoin taking the lead, the blockchain technology has been put in the spotlight as it introduced a method for multiple parties to achieve consensus without trust. Nevertheless, the according application is constrained due to its limitations in scalability. In this paper, we proposed a highly scalable consensus model based on majority voting cellular automata, namely the MOCA consensus, with a distinctive blockchain-based distributed ledger in which the state change of each node depends on its neighbors. MOCA consensus origins from the zero-temperature Ising model with spontaneous magnetization achieving scalability of number of nodes with high probability Byzantine fault tolerance.

Nedaa Baker Al Barghuthi, Hussam Juma Mohamed, Huwida Said

The emergence of blockchain technology has created a frenzy and a mind shift for organizations and industries. Governments and international bodies are increasingly discussing the potential implications of blockchain's distributed ledgers on business, governments and the economy. The intended purpose of the blockchain technology is to connect business network members in a decentralized way. The technology enables exchange and sharing of information without the involvement of intermediaries acting as arbitrators. Powered by its decentralized nature, the network will not have any single point of failure and will not rely on any single entity. Hence, blockchain eliminates the risks of centralization. This paper discusses a scenario of a blockchain technology in distributed ledgers to manage a well function and secure supply chain.

Tyler Crain, Vincent Gramoli, Mikel Larrea, Michel Raynal

This paper introduces a new leaderless Byzantine consensus called the Democratic Byzantine Fault Tolerance (DBFT) for blockchains. While most blockchain consensus protocols rely on a correct leader or coordinator to terminate, our algorithm can terminate even when its coordinator is faulty. The key idea is to allow processes to complete asynchronous rounds as soon as they receive a threshold of messages, instead of having to wait for a message from a coordinator that may be slow. The resulting decentralization is particularly appealing for blockchains for two reasons: (i) each node plays a similar role in the execution of the consensus, hence making the decision inherently “democratic” (ii) decentralization avoids bottlenecks by balancing the load, making the solution scalable. DBFT is deterministic, assumes partial synchrony, is resilience optimal, time optimal and does not need signatures. We first present a simple safe binary Byzantine consensus algorithm, modify it to ensure termination, and finally present an optimized reduction from multivalue consensus to binary consensus whose fast path terminates in 4 message delays.

Harish Sukhwani, Nan Wang, Kishor S. Trivedi, Andy Rindos

Hyperledger Fabric (HLF) is an open-source implementation of a distributed ledger platform for running smart contracts in a modular architecture. In this paper, we present a performance model of Hyperledger Fabric v1.0+ using Stochastic Reward Nets (SRN). From our detailed model, we can compute the throughput, utilization and mean queue length at each peer and critical processing stages within a peer. To validate our model, we setup an HLF network in our lab and run workload using Hyperledger Caliper. From our analysis results, we find that time to complete the endorsement process is significantly affected by the number of peers and policies such as AND (). The performance bottleneck of the ordering service and ledger write can be mitigated using a larger block size, albeit with an increase in latency. For the committing peer, the transaction validation check (using Validation System Chaincode (VSCC)) is a time-consuming step, but its performance impact can be easily mitigated since it can be parallelized. However, its performance is critical, since it absorbs the shock of bursty block arrivals. We also analyze various what-if scenarios, such as peers processing transactions in a pipeline, and multiple endorsers per organization.

He Haiwu, Yan An, Zehua Chen

With the vigorous development of blockchain technology represented by Bitcoin, blockchain technology has gradually surpassed the era of programmable currency and entered the era of smart contracts. Smart contracts are event- driven and stateful. With the in-depth development of blockchain technology, smart contracts use protocols and user interfaces to complete all steps of the contract process, allowing users to implement personalized code logic on the blockchain. Contract technology has the characteristics of decentralization, autonomy, observability, verifiability, and information sharing. It can effectively build programmable finance and programmable society, and is widely used in digital payment, financial asset disposal, multi-signature contracts, cloud computing, Internet of Things, sharing economy and other fields. First, it explains the basic concepts, full life cycle, basic classification, basic structure, key technologies, development status and main technology platforms of smart contracts; then discusses the application scenarios and development issues of smart contract technology, aiming to provide smart contract technology. The research and development provides reference.

Emmanuelle Anceaume, Antoine Guellier, Romaric Ludinard, Bruno Séricola

We propose a new way to organise both transactions and blocks in a distributed ledger to address the performance issues of permissionless ledgers. In contrast to most of the existing solutions in which the ledger is a chain of blocks extracted from a tree or a graph of chains, we present a distributed ledger whose structure is a balanced directed acyclic graph of blocks. We call this specific graph a SYC-DAG. We show that a SYC-DAG allows us to keep all the remarkable properties of the Bitcoin blockchain in terms of security, immutability, and transparency, while enjoying higher throughput and self-adaptivity to transactions demand. To the best of our knowledge, such a design has never been proposed so far.

Jaya Ram Menda

Financial settlement systems have long depended on batch-oriented processing pipelines that introduce substantial operational latency, delayed reconciliation cycles, and significant infrastructure overhead, limiting their ability to support increasingly real-time financial ecosystems. With the rapid growth of digital payments, algorithmic trading, and instantaneous fund transfers, financial institutions now require settlement architectures capable of sustaining high throughput, low-latency execution while ensuring correctness, durability, auditability, and strict regulatory compliance. This paper proposes a fully streaming-based settlement architecture built on Apache Kafka Streams, which provides distributed, stateful stream processing with exactly-once semantics, deterministic event ordering, and fault-tolerant recovery, combined with Apache Cassandra as a linearly scalable, highly available distributed state store for ledger materialization and durable transaction history. We outline essential design patterns such as idempotent event handling, monotonic ordering within partitions, ledger versioning strategies, and continuous reconciliation pipelines and examine how these patterns have been validated through publicly available prototypes and industrial implementations across the financial sector. Experimental findings demonstrate that integrating Kafka Streams with Cassandra enables near-real-time settlement processing with millisecond-range end-to-end latency and predictable fault recovery while preserving strong application-level consistency, ultimately offering a resilient and future-ready foundation for modern financial settlement infrastructures.

Ankur Sharma, Felix Schuhknecht, Divya Agrawal, Jens Dittrich

Within the last few years, a countless number of blockchain systems have emerged on the market, each one claiming to revolutionize the way of distributed transaction processing in one way or the other. Many blockchain features, such as byzantine fault tolerance (BFT), are indeed valuable additions in modern environments. However, despite all the hype around the technology, many of the challenges that blockchain systems have to face are fundamental transaction management problems. These are largely shared with traditional database systems, which have been around for decades already. These similarities become especially visible for systems, that blur the lines between blockchain systems and classical database systems. A great example of this is Hyperledger Fabric, an open-source permissioned blockchain system under development by IBM. By having a relaxed view on BFT, the transaction pipeline of Fabric highly resembles the workflow of classical distributed databases systems. This raises two questions: (1) Which conceptual similarities and differences do actually exist between a system such as Fabric and a classical distributed database system? (2) Is it possible to improve on the performance of Fabric by transitioning technology from the database world to blockchains and thus blurring the lines between these two types of systems even further? To tackle these questions, we first explore Fabric from the perspective of database research, where we observe weaknesses in the transaction pipeline. We then solve these issues by transitioning well-understood database concepts to Fabric, namely transaction reordering as well as early transaction abort. Our experimental evaluation shows that our improved version Fabric++ significantly increases the throughput of successful transactions over the vanilla version by up to a factor of 3x.

Aashish Kolluri, Ivica Nikolić, Ilya Sergey, Aquinas Hobor · 5 authors

We investigate a family of bugs in blockchain-based smart contracts, which we call event-ordering (or EO) bugs. These bugs are intimately related to the dynamic ordering of contract events, i.e., calls of its functions on the blockchain, and enable potential exploits of millions of USD worth of Ether. Known examples of such bugs and prior techniques to detect them have been restricted to a small number of event orderings, typicall 1 or 2. Our work provides a new formulation of this general class of EO bugs as finding concurrency properties arising in long permutations of such events. The technical challenge in detecting our formulation of EO bugs is the inherent combinatorial blowup in path and state space analysis, even for simple contracts. We propose the first use of partial-order reduction techniques, using happen-before relations extracted automatically for contracts, along with several other optimizations built on a dynamic symbolic execution technique. We build an automatic tool called ETHRACER that requires no hints from users and runs directly on Ethereum bytecode. It flags 7-11% of over ten thousand contracts analyzed in roughly 18.5 minutes per contract, providing compact event traces that human analysts can run as witnesses. These witnesses are so compact that confirmations require only a few minutes of human effort. Half of the flagged contracts have subtle EO bugs, including in ERC-20 contracts that carry hundreds of millions of dollars worth of Ether. Thus, ETHRACER is effective at detecting a subtle yet dangerous class of bugs which existing tools miss.