Blockchain Papers

Cyril Naves Samuel, François Verdier, Severine Glock, Patricia Guitton-Ouhamou

No abstract is available for this record.

Tayyaba Noreen, Qiufen Xia, Muhammad Zeeshan Haider

In the past decade, blockchain has emerged as a promising solution for building secure distributed ledgers and has attracted significant attention. However, current blockchain systems suffer from limited throughput, poor scalability, and high latency. Due to limitations in consensus mechanisms, especially in managing node identities, blockchain is often considered unsuitable for applications such as the Internet of Things (IoT). This paper proposes the Advanced DAG-based Ranking (ADR) protocol to enhance blockchain scalability and throughput. ADR employs a directed acyclic graph (DAG) structure where nodes are positioned based on their rankings. Unlike traditional chains, ADR allows honest nodes to write blocks and verify transactions using a DAG-based topology. The protocol follows a three-step approach to secure the network against double-spending and enhance performance. First, it verifies nodes using their public and private keys before granting entry. Second, it builds an advanced DAG ledger enabling block production and transaction validation. Third, a ranking algorithm filters out malicious nodes, ranks the remaining nodes based on performance, and arranges them topologically. This process increases throughput and ensures robust scalability. We evaluated ADR on Amazon EC2 clusters with over 100 nodes, including scenarios with injected malicious nodes. Simulation results demonstrate that ADR significantly improves transaction throughput and network liveness compared to existing DAG-based blockchains such as IOTA and ByteBall, making it well-suited for IoT applications.

Peter Gaži, Ling Ren, Alexander Russell

No abstract is available for this record.

Jiewei Feng

Blockchain and other decentralized databases, known as distributed ledgers, are designed to store information online where all trusted network members can update the data with transparency. The dynamics of ledger's development can be mathematically represented by a directed acyclic graph (DAG). In the first part of the thesis, we propose a random DAG model with sequential stochastic arrivals that mimic attachment rules from the IOTA cryptocurrency and study its asymptotic behavior as time goes to infinity. Our analysis establishes that the DAG is almost surely one-ended which is a crucial indicator of security of a decentralized database. In the second part of the paper, we study a modified DAG model and analyze its property as the arrival rate goes to infinity and the inter arrival time goes to zero. We establish that the number of leaves in the DAG and various random variables characterizing the vertices in the DAG can be approximated by its fluid limit, represented as delayed partial differential equations. Furthermore, we establish the stable state of this fluid limit and validate our findings through simulations.--Author's abstract

Chryssis Georgiou, Michel Raynal, Elad M. Schiller

Numerous distributed applications, such as cloud computing and distributed ledgers, necessitate the system to invoke asynchronous consensus objects an unbounded number of times, where the completion of one consensus instance is followed by the invocation of another. With only a constant number of objects available, object reuse becomes vital. We investigate the challenge of object recycling in the presence of Byzantine processes, which can deviate from the algorithm code in any manner. Our solution must also be self-stabilizing, as it is a powerful notion of fault tolerance. Self-stabilizing systems can recover automatically after the occurrence of arbitrary transient faults, in addition to tolerating communication and (Byzantine or crash) process failures, provided the algorithm code remains intact. We provide a recycling mechanism for asynchronous objects that enables their reuse once their task has ended, and all non-faulty processes have retrieved the decided values. This mechanism relies on synchrony assumptions and builds on a new self-stabilizing Byzantine-tolerant synchronous multivalued consensus algorithm, along with a novel composition of existing techniques.

Christ, Miranda, Choi, Kevin, McKelvie, Walter, Bonneau, Joseph · 5 authors

A Single Secret Leader Election (SSLE) enables a group of parties to randomly choose exactly one leader from the group with the restriction that the identity of the leader will be known to the chosen leader and nobody else. At a later time, the elected leader should be able to publicly reveal her identity and prove that she is the elected leader. The election process itself should work properly even if many registered users are passive and do not send any messages. SSLE is used to strengthen the security of proof-of-stake consensus protocols by ensuring that the identity of the block proposer remains unknown until the proposer publishes a block. Boneh, Eskandarian, Hanzlik, and Greco (AFT'20) defined the concept of an SSLE and gave several constructions. Their most efficient construction is based on the difficulty of the Decision Diffie-Hellman problem in a cyclic group. In this work we construct the first efficient SSLE protocols based on the standard Learning With Errors (LWE) problem on integer lattices, as well as the Ring-LWE problem. Both are believed to be post-quantum secure. Our constructions generalize the paradigm of Boneh et al. by introducing the concept of a re-randomizable commitment (RRC). We then construct several post-quantum RRC schemes from lattice assumptions and prove the security of the derived SSLE protocols. Constructing a lattice-based RRC scheme is non-trivial, and may be of independent interest.

Dylan Yu, Yi‐Chen E. Yang, Alissa Shen, Dan E. Tamir · 5 authors

No abstract is available for this record.

Ben Charoenwong, Robert M. Kirby, Jonathan Reiter

We examine which decentralized finance architectures enable meaningful regulation by combining financial and computational theory. We show via deduction that a decentralized and permissionless Turing-complete system cannot provably comply with regulations concerning anti-money laundering, know-your-client obligations, some securities restrictions and forms of exchange control. Any system that claims to follow regulations must choose either a form of permission or a less-than-Turing-complete update facility. Compliant decentralized systems can be constructed only by compromising on the richness of permissible changes. Regulatory authorities must accept new tradeoffs that limit their enforcement powers if they want to approve permissionless platforms formally. Our analysis demonstrates that the fundamental constraints of computation theory have direct implications for financial regulation. By mapping regulatory requirements onto computational models, we characterize which types of automated compliance are achievable and which are provably impossible. This framework allows us to move beyond traditional debates about regulatory effectiveness to establish concrete boundaries for automated enforcement.

Pengfei Huang, Wanqing Jie, Arthur Sandor Voundi Koe, Ruitao Hou · 9 authors

No abstract is available for this record.

Massimo Franceschet, Andrea Antonutti, Luca Donno

We propose a novel model for teaching and learning called Decentralized Autonomous Education (DAE for short). DAE exploits the dual principles of freedom and responsibility, meritocracy and inclusivity, privacy and transparency in the educational process. It also fits well the philosophy of blockchain technology, and more generally of Web3 – the third iteration of the World Wide Web – specifically the tenets of decentralization, disintermediation, incentive and sovereignty of the individual. In this paper, we fully illustrate the DAE model, highlighting the theoretical and practical links between DAE and Web3, dissecting the pros and cons of the proposed learning method and reviewing related pedagogical approaches. Finally, we describe the front-end and back-end design of the DAE app, a decentralized application that implements the DAE learning model.

Kenji Saito, Akihide Uchida

No abstract is available for this record.

Morena Barboni, Guglielmo De Angelis, Andrea Morichetta, Andrea Polini

No abstract is available for this record.

Deepanjan Mitra, Agostino Cortesi, Nabendu Chaki

No abstract is available for this record.

Robin Linus

No abstract is available for this record.

Elvira Albert, Jesús Correas, Pablo Gordillo, Guillermo Román‐Díez · 5 authors

Abstract Efficiency is a fundamental property of any type of program, but it is even more so in the context of the programs executing on the blockchain (known as smart contracts ). This is because optimizing smart contracts has direct consequences on reducing the costs of deploying and executing the contracts, as there are fees to pay related to their bytes-size and to their resource consumption (called gas ). Optimizing memory usage is considered a challenging problem that, among other things, requires a precise inference of the memory locations being accessed. This is also the case for the Ethereum Virtual Machine (EVM) bytecode generated by the most-widely used compiler, , whose rather unconventional and low-level memory usage challenges automated reasoning. This paper presents a static analysis, developed at the level of the EVM bytecode generated by , that infers write memory accesses that are needless and thus can be safely removed. The application of our implementation on more than 19,000 real smart contracts has detected about 6,200 needless write accesses in less than 4 hours. Interestingly, many of these writes were involved in memory usage patterns generated by that can be greatly optimized by removing entire blocks of bytecodes. To the best of our knowledge, existing optimization tools cannot infer such needless write accesses, and hence cannot detect these inefficiencies that affect both the deployment and the execution costs of Ethereum smart contracts.

Nickolas Carter, Duane Davis, Cynthia E. Irvine, Peter Pommer

Autonomous multi-vehicle systems are becoming increasingly relevant in military operations and have demonstrated potential applicability in civilian environments as well. A problem emerges, however, when logging data within these systems. In particular, potential loss of individual vehicles and inherently lossy and noisy communications environments can result in the loss of important mission data. This paper describes a novel distributed ledger protocol that can be used to ensure that the data in such a system survives and documents verification of the behavioral correctness of this protocol using informal verification methods and tools provided by the Monterey Phoenix project.

Kenji Saito, Yutaka Soejima, Toshihiko Sugiura, Yukinobu Kitamura · 5 authors

Since the Merge update upon which Ethereum transitioned to Proof of Stake, it has been touted that it resulted in lower power consumption and increased security. However, even if that is the case, can this state be sustained? In this paper, we focus on the potential impact of competition with other smart contract platforms on the price of Ethereum's native currency, Ether (ETH), thereby raising questions about the safety and sustainability purportedly brought about by the design of Proof of Stake.

Marc Leinweber, Niclas Kannengießer, Hannes Hartenstein, Ali Sunyaev

No abstract is available for this record.

Franck Cassez, Joanne Fuller, Milad K. Ghale, David J. Pearce · 5 authors

The Ethereum protocol implements a replicated state machine. The network participants keep track of the system state by: 1) agreeing on the sequence of transactions to be processed and 2) computing the state transitions that correspond to the sequence of transactions. Ethereum transactions are programs, called smart contracts, and computing a state transition requires executing some code. The Ethereum Virtual Machine (EVM) provides this capability and can execute programs written in EVM bytecode. We present a formal and executable semantics of the EVM written in the verification-friendly language Dafny: it provides (i) a readable, formal and verified specification of the semantics of the EVM; (ii) a framework to formally reason about bytecode.

Christian Schmitz, Martin Užík

No abstract is available for this record.

Fernando Bereta dos Reis, Mark Borkum, Monish Mukherjee, D. Jonathan Sebastian-Cardenas

This paper explores the potential of distributed ledger technology (DLT) to improve fault-tolerant grid operations by leveraging its core features as an immutable, decentralized ledger, a distributed, consensus-based agreement process, and a distributed state-replication engine. Distribution power systems deliver electricity to millions of customers; however, they are susceptible to various threats that can result in customer interruptions. These include faults caused by adverse weather conditions, natural disasters, vegetation growth, equipment failure, and malicious attacks. To minimize the effects of these faults, fault-handling approaches rely on network knowledge to isolate affected areas and reconnect unaffected areas, reducing the number of affected customers while maintaining safety. Here, we present a trusted data-sharing architecture that enables independent, distributed actors to reconstruct the pre-fault system state by enabling distributed resources to make appropriate decisions with limited network/system information. Although the process requires some data sharing between switch-delimited areas, the approach limits the amount of private information shared, preserving customers’ privacy and business-sensitive information. We include three use cases that form a foundation for third parties to develop functional solutions that can eventually be deployed in the field. The gross error detection method used within switch-delimited areas can identify sensor errors and accurately detect circuit breaker states. The evaluation of possible reconnection while preserving data ownership resulted in a voltage magnitude difference smaller than 0.01% from the OpenDSS power flow solution that has full system knowledge, which is below the expected power flow tolerance. The approach offers a promising opportunity for improving fault-tolerant distribution grid operations.

Stamatis Papangelou, Klitos Christodoulou, George Michoulis

No abstract is available for this record.

Nikolay Ivanov, Qiben Yan, Anurag Kompalli

Ethereum is a permissionless blockchain ecosystem that supports execution of smart contracts, the key enablers of decentralized finance (DeFi) and non-fungible tokens (NFT). However, the expressiveness of Ethereum smart contracts is a double-edged sword: while it enables blockchain programmability, it also introduces security vulnerabilities, i.e., the exploitable discrepancies between expected and actual behaviors of the contract code. To address these discrepancies and increase the vulnerability coverage, we propose a new smart contract security testing approach called transaction encapsulation. The core idea lies in the local execution of transactions on a fully-synchronized yet isolated Ethereum node, which creates a preview of outcomes of transaction sequences on the current state of blockchain. This approach poses a critical technical challenge — the well-known time-of-check/time-of-use (TOCTOU) problem, i.e., the assurance that the final transactions will exhibit the same execution paths as the encapsulated test transactions. In this work, we determine the exact conditions for guaranteed execution path replicability of the tested transactions. To demonstrate the transaction encapsulation, we implement a transaction testing tool, TxT, which reveals the actual outcomes (either benign or malicious) of Ethereum transactions. To ensure the correctness of testing, TxT deterministically verifies whether a given sequence of transactions ensues an identical execution path on the current state of blockchain. We analyze over 1.3 billion Ethereum transactions and determine that 96.5% of them can be verified by TxT. We further show that TxT successfully reveals the suspicious behaviors associated with 31 out of 37 vulnerabilities (83.8% coverage) in the smart contract weakness classification (SWC) registry. In comparison, the vulnerability coverage of all the existing defense approaches combined only reaches 40.5%.

Junfeng Tian, Junfeng Tian, Jin Tian, Jin Tian · 5 authors

No abstract is available for this record.