The InterPlanetary File System (IPFS) has recently gained considerable attention. While prior research has focused on understanding its performance characterization and application support, it remains unclear: (1) what kind of files/content are stored in IPFS, (2) who are providing these files, (3) are these files always accessible, and (4) what affects the file access performance. To answer these questions, in this paper, we perform measurement and analysis on over 4 million files associated with CIDs (content IDs) that appeared in publicly available IPFS datasets. Our results reveal the following key findings: (1) Mixed file accessibility: while IPFS is not designed for a permanent storage, accessing a non-trivial portion of files, such as those of NFTs and video streams, often requires multiple retrieval attempts, potentially blocking NFT transactions and negatively affecting the user experience. (2) Dominance of NFT (non-fungible token) and video files: about 50% of stored files are NFT-related, followed by a large portion of video files, among which about half are pirated movies and adult content. (3) Centralization of content providers: a small number of peers (top-50), mostly cloud nodes hosted by tech companies, serve a large portion (95%) of files, deviating from IPFS's intended design goal. (4) High variation of downloading throughput and lookup time: large file retrievals experience lower average throughput due to more overhead for resolving file chunk CIDs, and looking up files hosted by non-cloud nodes takes longer. We hope that our findings can offer valuable insights for (1) IPFS application developers to take into consideration these characteristics when building applications on top of IPFS, and (2) IPFS system developers to improve IPFS and similar systems to be developed for Web3.
Sharding is one of the most promising techniques for improving blockchain scalability. In blockchain state sharding, account migration across shards is crucial to the low ratio of cross-shard transactions and cross-shard workload balance. Through reviewing state-of-the-art protocols proposed to reconfigure blockchain shards via account shuffling, we find that account migration plays a significant role. From the literature, we only find a related work that utilizes the lock mechanism to realize account migration. We call this method the SOTA Lock, in which both the target account’s state and its associated transactions need to be locked when migrating this account between shards. Thereby, SOTA Lock causes a high makespan to the associated transactions. To address these challenges of account migration, we propose a dedicated Fine-tuned Lock protocol. Unlike SOTA Lock, Fine-tuned Lock enables real-time processing of the affected transactions during account migration. Thus, the makespan of associated transactions can be lowered. We implement Fine-tuned Lock protocol using an open-sourced blockchain testbed (i.e., BlockEmulator) and deploy it in Tencent cloud. The experimental results show that the proposed Fine-tuned Lock outperforms the SOTA Lock in terms of transaction makespan. For example, the transaction makespan of Fine-tuned Lock achieves around 30% the makespan of SOTA Lock.
Payment Channel Networks (PCNs) have been proposed as a second-layer solution to the scalability issue of blockchain-based cryptocurrencies, most developed systems still lack effective strategies for further scalability solutions. Virtual payment channel (VPC) has been proposed as an off-chain technique that avoids the involvement of intermediaries for payments in a PCN. However, there is no research on how to efficiently construct VPCs while considering the characteristics of the underlying PCN. To fill this void, this paper focuses on the VPC construction in a PCN. More specifically, we propose a metric, Capacity to the Number of Intermediaries Ratio (CNIR), to consider both the capacity of the constructed VPC and the collateral locked by the involved users. We first study the VPC construction problem for a single pair of users and design an efficient algorithm that achieves the optimal CNIR. Based on this, we propose Thor, a protocol that constructs a virtual payment channel network (VPCN) for multiple pairs. Evaluation results show that Thor can efficiently construct a VPCN and outperform baseline algorithms in terms of the CNIR.
Cross-shard Transactions (CTXs) widely exist in sharded blockchains. CTXs have to endure large confirmation latency because they need to participate in consensus in both their source and destination shards. To diminish CTXs, plenty of state-of-the-art blockchain protocols have been proposed. For example, in BrokerChain [1], some intermediary broker accounts can help turn CTXs into intra-shard transactions through their voluntary liquidity services. Thereby, the original CTXs can be confirmed in blockchain shards quickly. However, we found that BrokerChain is impractical for a sharded blockchain because it does not consider how to recruit a sufficient number of broker accounts. Thus, blockchain clients do not have the motivation to provide token liquidity for others. To address this challenge, we design Broker2Earn, which is essentially a decentralized finance (DeFi) protocol that works as an incentive mechanism for blockchain users who choose to become brokers. Via participating in Broker2Earn, brokers can earn native revenues when they collateralize their tokens to the protocol. Furthermore, Broker2Earn can also benefit the sharded blockchain since it can efficiently spend each staked liquidity provided by brokers on diminishing CTXs. We formulate the core module of Broker2Earn into a revenue-maximization problem, which is proven NP-hard. To solve this problem, we design an online approximation algorithm using the relax-and-rounding technique. We also rigorously analyze the approximation ratio of our online algorithm. Finally, we conduct extensive experiments using real-world Ethereum transactions on both a transaction-driven simulator and an open-source blockchain testbed. The evaluation results show that the proposed Broker2Earn protocol demonstrates a near-optimal performance that outperforms other baselines, in terms of broker revenues and the usage of system liquidity.
Shan Wang, Ming Yang, Wenxuan Dai, Yu Liu · 6 authors
Third-party RPC services have become the mainstream way for users to access Ethereum. In this paper, we present a novel deanonymization attack that can link an Ethereum address to a real-world identity such as IP address of a user who accesses Ethereum via a third-party RPC service. We find that RPC API calls result in distinguishable sizes of encrypted TCP packets. An attacker can then find when a user sends a transaction to an RPC provider and immediately send a beacon transaction after the user transaction. By exploiting the differences in the distributions of inter-arrival time intervals of normal transactions and two simultaneously initiated transactions, the attacker can identify the victim transaction in the Ethereum network. This enables the attacker to correlate the Ethereum address of the victim transaction’s initiator with the source IP address of TCP packets from a victim user. We model the attack through empirical measurements and conduct extensive real-world experiments to validate the effectiveness of our attack. With three optimization strategies, the correlation accuracy can reach to 98.70% and 96.60% respectively in Ethereum testnet and mainnet. We are the first to study the deanonymization of Ethereum users behind third-party RPC services.
Peiyao Sheng, Chenyuan Wu, Dahlia Malkhi, Michael K. Reiter · 7 authors
This paper introduces and develops the concept of ``ticketing'', through which atomic broadcasts are orchestrated by nodes in a distributed system. The paper studies different ticketing regimes that allow parallelism, yet prevent slow nodes from hampering overall progress. It introduces a hybrid scheme which combines managed and unmanaged ticketing regimes, striking a balance between adaptivity and resilience. The performance evaluation demonstrates how managed and unmanaged ticketing regimes benefit throughput in systems with heterogeneous resources both in static and dynamic scenarios, with the managed ticketing regime performing better among the two as it adapts better. Finally, it demonstrates how using the hybrid ticketing regime performance can enjoy both the adaptivity of the managed regime and the liveness guarantees of the unmanaged regime.
Public and permissionless blockchain systems are challenged by Sybil attacks, in which attackers use multiple identities to gain control.Traditionally, such attacks are prevented by consensus mechanisms relying on resource expenditure.However, such mechanisms (e.g.proof of work) face criticism for being wasteful.To address this and other concerns, novel blockchain systems backed by new consensus mechanisms have recently emerged.We formalise three key characteristics pursued by these systems: permissionlessness, Sybil attack resistance, and freeness.We demonstrate that no blockchain protocol can simultaneously achieve all three characteristics within the paradigm established by our formalisation.Thus, a trilemma emerges for distributed ledger technology designers, who must balance these characteristics thoughtfully.
Today, blockchain technology has found a special role in the energy industry and has various applications. In this paper a token-based peer-to-peer energy trading model is presented. Since the peer-to-peer trading of energy leads to the growth of micro-grids and smart grids, which in turn play a vital role in the development of renewable energies, using blockchain is the best and safest way to develop peer-to-peer networks. The definition of a special token can lead to balance and relative independence of the price of energy supply, which means that the price of network energy is related to the price of the token, and if the token is accepted, the growth of the network is inevitable. This can be one of the best ways for the growth of renewable energies, considering the renewable energy sources in the network. After reviewing the model, a sample smart contract corresponding to this model has been implemented on the Ethereum local blockchain platform.
The widespread availability of Internet access and online services has led to the generation of numerous large-scale graphs in various real-world applications, such as online social networks and knowledge graphs. Keyword search stands out as a crucial task in the analysis and mining of these graphs. However, graph data owners tend to outsource storage and computation tasks to the cloud due to limited computing and storage resources. In this case, it is critical to ensure the integrity of the query results, as the cloud may have an incentive to return tampered results to serve its own interests. Currently, blockchain systems can store data efficiently and securely, creating a decentralized, tamper-proof digital platform. This functionality positions blockchain as a crucial complement and enhancement to traditional cloud storage solutions. Mainstream blockchains use a hybrid storage system to improve scalability, storing small meta-data on-chain and outsourcing raw data off-chain. While cryptographic proofs protect data integrity for queries, current schemes only support key-value data. This paper pioneers the study of authenticated keyword searches on graphs in hybrid-storage blockchains. The key challenge is to design an authenticated data structure (ADS) based on the graph data that can efficiently deal with keyword search queries. We propose Merkle Path DAG (MP-DAG), a novel ADS that aggregates the unqualified paths that will not appear in the result trees to efficiently handle authenticated keyword search queries on graphs. Furthermore, to reduce the ADS storage cost, we design an optimization scheme MP-DAG* by combining the similar subgraphs of MP-DAG. Experimental results demonstrate the performance of the proposed ADS and optimization measure.
Virtual Power Plant (VPP), as a technology for the aggregated management of distributed resources, has received extensive research and application. Concurrently, as the process of power market reform advances, the collaborative operation of multiple VPPs has become a crucial research focus. Against this backdrop, this paper proposes a decentralized collaborative governance model for multiple virtual power plants based on the blockchain Delegated Proof of Stake (DPoS) consensus mechanism. Considering the dual characteristics of source and load in VPPs, a singular VPP scheduling model is introduced. The paper outlines the process of the blockchain DPoS consensus mechanism and introduces a decentralized iterative pricing mechanism for multiple virtual power plant systems. This mechanism, combined with the DPoS consensus mechanism, utilizes witness nodes as multi-centralized entities to safeguard against malicious attacks and single-point failures. Finally, case studies validate the effectiveness and rationality of the proposed model.
Daiki Ito, Yuta Takata, Hiroshi Kumagai, Masaki Kamizono
Traditionally, top-level domains (TLDs) are managed by the Internet corporation for assigned names and numbers (ICANN), and the domain names under them are managed by registrars. Against such a centralized management, a blockchain naming service (BNS) has been proposed to manage TLDs on blockchains without authority intervention. BNS users can register TLD strings as non-fungible tokens and manage the TLD root zone. However, such a decentralized management results in the introduction of a new security issue, BNS TLD name collision, wherein the same TLD is registered in several different BNSs. In this study, we investigated BNS TLD name collisions by analyzing TLDs registered on two BNSs: Handshake and Decentraweb. Specifically, we collected TLDs registered in Handshake and Decentraweb and the associated data, and analyzed the data registration status of BNS TLDs and BNS TLD name collisions. The analysis of 11,595,406 Handshake and 11,889 Decentraweb TLDs revealed 6,973 BNS TLD name collisions. In particular, lastname TLDs, which are intended for use as person names, yielded a large number of registered domain names. In addition, the analysis identified 10 name collisions between the BNS and operational ICANN TLDs. Further, the ICANN TLD candidates under review also had name collisions against the BNS TLDs. Consequently, based on the characteristics of these name collisions and discussions in BNS communities, we considered countermeasures against BNS TLD name collisions. For the further development of BNSs, we believe that it is essential to discuss with the existing Internet communities and coexist with the existing Internet.
The adoption of blockchain technology has catalyzed the expansion of decentralized finance (DeFi), leading to the harnessing of blockchain platforms. However, the decentralization of blockchain has given rise to blockchain extractable value (BEV) activities, influenced by consensus mechanisms. This study centers on BEV, unveiling a real-time discovery and mining system (RDMS) tailored for arbitrage-based DeFi activities. The system employs innovative methodologies for localized computation and execution. It establishes a comprehensive monitoring system for arbitrage and liquidation activities, contributing positively to the DeFi ecosystem. Leveraging round-the-clock on-chain data indexing and event-driven parsing methods, the RDMS enables automated and periodic analysis of BEV activities. This system provides valuable insights for BEV research, particularly in the context of arbitrage and liquidation activities. And we are able to consistently extract value using arbitrage strategies on blockchains, using RDMS that monitors the chain in real time and applies gas cost reduction mechanisms. Experimental testing and comparative analysis validate the RDMS’s effectiveness, showcasing minimal latency and remarkable gas optimization capabilities.
With the large increase in the adoption of blockchain technologies, their underlying peer-to-peer networks must also scale with the demand. In this context, previous works highlighted the importance of ensuring efficient and resilient communication for the underlying consensus and replication mechanisms. However, they were mainly focused on mainstream, Proof-of-Work-based Distributed Ledger Technologies like Bitcoin or Ethereum. In this paper, the problem is investigated in the context of consensus-validation based blockchains, like the XRP Ledger. The latter relies on a Federated Byzantine Agreement (FBA) consensus mechanism which is proven to have a good scalability in regards to transaction throughput. However, it is known that significant increases in the size of the XRP Ledger network would be challenging to achieve. The main reason is the flooding mechanism used to disseminate the messages related to the consensus protocol, which creates many duplicates in the network. Squelching is a recent solution proposed for limiting this duplication, however, it was never evaluated quantitatively in real-life scenarios involving the XRPL production network. In this paper, our aim is to assess this mechanism using a real-life controllable testbed and the XRPL production network, to assess its benefit and compare it to alternative solutions relying on Named Data Networking and on a gossip-based approach.
Cloud storage is crucial for managing large datasets, but dependence on a single cloud space raises security concerns. Conversely, Distributed Ledger Technology (DLT) provides a secure cloud-based storage system operating on a peer-to-peer network. In our proposed system, user files are encrypted and distributed across multiple peers using the Interplanetary File System (IPFS) protocol, with hash values stored in the DLT. This project integrates DLT and a cloud platform for storing files from various users. Our project, Distributed Cloud File Sharing Technology (DCFST), merges distributed computing principles with cloud technology to overcome traditional file-sharing limitations. It enables secure file sharing, storage, and access across interconnected devices, ensuring data integrity and authentication through blockchain. Smart contracts automate access control, granting precise content control to users. DCFST orchestrates a peer-to-peer network of nodes, with a central coordinator managing node discovery, file indexing, and load balancing. The implementation utilizes Python, J avaScrlpt, and Ethereum for smart contract execution. DCFST introduces a resilient, user-centric file-sharing ecosystem by merging distributed systems with cloud infrastructure. It contributes to decentralized technology evolution, revolutionizing data collaboration and access paradigms.
Land registration is one of the most complex processes in India, which includes a lot of bureaucratic steps and consumes a good chunk of resources, both financial and time. Due to this complex process and waiting time, the public tends to go through middlemen and third-party agents, which sometimes leads to fraud. This paper provides a detailed review and limitations of the current land registry system, both paper-oriented and centralized online system, as well as a review of current research on blockchain-based land registry processes. To make the land registry system more secure and faster than the available solutions, this proposes a modified solution that will mitigate the limitations of the related work by using a three-tier structure, including a government body responsible for taking permission and overlooking the entire transaction, a buyer or seller, and further banks responsible for overlooking payment transactions. The three parties approve the transaction, and then the transaction details are added to the Ethereum blockchain network. The solution also solves the transaction size issue by storing the meta data on the main chain and non-transactional data on the IPFS network, which will significantly reduce the load on the network.
As social media grows to entangle and remould the lives of people, so grows the concern over data privacy, censorship, server outages, and control over personal information by proprietary bodies due to their centralized design. The rise of blockchain has encouraged researchers to consider the decentralization framework for developing online social networks to resolve the challenges mentioned above. In a decentralized ecosystem, no one entity has absolute access to data and the power to enforce arbitrary decisions. The benefits of this include ownership over personal data, censorship resistance, data security, and improved control over user-generated content. In this paper, we propose the design of Ethnos, a social networking application built to harness the powers of blockchain and distributed storage technology to heighten the security and reliability of users as well as their data. In that context, suitable smart contracts have been fabricated. This paper also prospects integration of two-factor user authentication and trust score checks with Ethnos to corroborate the trustworthiness of both user and data. In addition, Ethnos incorporates a remuneration system to compensate users for their contribution to and engagement with the platform.
Kevin Werbach, Primavera De Filippi, Joshua Tan, Gina Pieters
Blockchain Governance in the Wild 2 Our work differs from the existing literature in three significant ways. Firstly, there has been very little comparative work among different blockchain networks or communities-what exists generally focuses only on Bitcoin and Ethereum at most. Secondly, this is not a theoretical study of potential successes or failures: We instead survey practical implementations, and governance development plans of specific projects. Finally, we do not examine only the governance decisions encoded on-chain. Our work expands to consider social norms, informal practices, and institutional governing entities associated with the project outside of the code. We believe this paper is the first to formally document and highlight the importance of informal governance structures within blockchain projects.
In blockchain-based data marketplaces, the cross-chain solution based on relay chains has become an effective way to support digital asset transfer between heterogeneous blockchains. If a digital asset is popular, it will be frequently transferred between multiple data marketplaces. Digital assets are typically represented as (Non-fungible Tokens) NFTs. However, when utilizing a cross-chain transfer scheme based on a relay chain that involves locking, unlocking and burning of the NFT, it can lead to significant transaction costs. Due to the frequent minting and burning of popular NFTs, they tend to consume a significant amount of gas, resulting in high transaction costs. To address this issue, we propose the DART scheme, a secure and low-cost cross-chain transaction scheme for popular digital assets based on (dynamic NFT) DNFT and relay chain. The scheme mainly includes three aspects: Firstly, the initial owner of (Data NFT) DataNFT locks it onto the gateway contract on SChain, mints a (Cross-chain NFT) CNFT on the relay chain that references the DataNFT for resale, and minted DataNFT on the destination blockchain until the CNFT is no longer being resold. Secondly, the DNFT standard is utilized to implement CNFTs. The DNFT standard records the transaction hash of each CNFT resale, ensuring the secure reselling of DataNFTs. Thirdly, the metadata of DataNFT is encrypted to ensure its security during cross-chain transmission. Finally, we selected Axelar Network as the relay network and successfully implemented a prototype of the system. The experimental results demonstrate the feasibility of our proposed scheme.
There are a series of challenges in microgrid transactions, and blockchain technology holds the promise of addressing these challenges. However, with the increasing number of users in microgrid transactions, existing blockchain systems may struggle to meet the growing demands for transactions. Therefore, this paper proposes an efficient and secure blockchain consensus algorithm designed to meet the demands of large-scale microgrid electricity transactions. The algorithm begins by utilizing a Spectral clustering algorithm to partition the blockchain network into different lower-level consensus set based on the transaction characteristics of nodes. Subsequently, a dual-layer consensus process is employed to enhance the efficiency of consensus. Additionally, we have designed a secure consensus set leader election strategy to promptly identify leaders with excellent performance. Finally, we have introduced an authentication method that combines zero-knowledge proofs and key sharing to further mitigate the risk of malicious nodes participating in the consensus. Theoretical analysis indicates that our proposed consensus algorithm, incorporating multiple layers of security measures, effectively withstands blockchain attacks such as denial of service. Simulation experiment results demonstrate that our algorithm outperforms similar blockchain algorithms significantly in terms of communication overhead, consensus latency, and throughput.
Online social networks (OSNs) have become integral to daily life, yet the prevalent centralized model of these platforms presents considerable challenges in terms of security, privacy, and management. In response to these concerns, a decentralized architecture underpinned by blockchain technology emerges as a promising solution. This paper delves into the development of an OSN service leveraging blockchain technology to facilitate decentralized operation, thereby addressing the aforementioned issues. Through the utilization of the Interplanetary Filesystem (IPFS), large volumes of low-security data are effectively decentralized, contributing to enhanced data integrity and accessibility. Furthermore, the establishment of a decentralized autonomous organization empowers users with greater autonomy, enabling democratic self-governance of the OSN. This innovative approach not only addresses existing shortcomings but also paves the way for a more resilient, transparent, and user-centric social networking paradigm.
M.S. Roobini, Chappidi Sindhuja, Chanda Shravan, Manju C Nair · 5 authors
In blockchain systems, transaction details are stored across a distributed ledger, and each peer bears the responsibility of upkeeping an identical replica of this ledger. This project explains the challenges faced by the high storage costs occurred in the traditional blockchain systems, where each peer maintains an identical copy of transaction data. A DSB system tries to tackle the high storage cost issue by incorporating cryptographic techniques. The Distributed Storage Blockchain (DSB) systems, however face communication costs during peer failures, which are often caused by denial-of-service attacks. To overcome these challenges, the DSB approach has been using a LSS approach. This method utilizes a hierarchical privacy scheme comprising a primary global secret node and multiple subordinate local secret nodes. The suggested Distributed Storage Blockchain (DSB) approach, incorporating Local Secret Sharing (LSS), enhances both storage efficiency and reduces recovery communication costs. This approach aims enhancing both the effectiveness of storage and reducing communication costs. During recovery processes. In the case of peer failures and security threats the DSB with LSS approach provides a solution for creating more resilient and resource-efficient blockchain systems.
In the mobile edge computing (MEC) environment, the edge caching can provide the timely data response service for the intelligent scenarios. However, due to the limited storage capacity of edge nodes and the malicious node behavior, the question of how to select the cached contents and realize the decentralized security data caching faces challenges. In this paper, a blockchain-based decentralized and proactive caching strategy is proposed in an MEC environment to address this problem. The novelty is that the blockchain was adopted in an MEC environment with a proactive caching strategy based on node utility, and the corresponding optimization problem was built. The blockchain was adopted to build a secure and reliable service environment. The employed methodology is that the optimal caching strategy was achieved based on the linear relaxation technology and the interior point method. Additionally, in a content caching system, there is a trade-off between cache space and node utility, and the caching strategy was proposed to solve this problem. There was also a trade-off between the consensus process delay of blockchain and the caching latency of content. An offline consensus authentication method was adopted to reduce the influence of the consensus process delay on the content caching. The key finding was that the proposed algorithm can reduce latency and can ensure the security data caching in an IoT environment. Finally, the simulation experiment showed that the proposed algorithm can achieve up to 49.32%, 43.11%, and 34.85% improvements on the cache hit rate, the average content response latency, and the average system utility, respectively, compared to the random content caching algorithm, and it achieved up to 9.67%, 8.11%, and 5.95% increases, successively, compared to the greedy content caching algorithm.
Distributed ledger technology (DLT) as an rising alternative for improving safety and transparency in reportsharing structures is very promising. In this regard, the existing have a look at is providing a blockchain-based system for file sharing where allotted ledgers may be used to conquer the restrictions of centralized structures. To make certain that the records shared is secure, unchangeable, and necessary, the gadget applies consensus, hashing, and encryption strategies. The use of clever contracts lets in for automatic execution of documentsharing transactions in a steady manner, thus lowering the capability risks associated with fraud or prison troubles. Furthermore, users are furnished with more control by letting them specify permissions and get right of entry to constraints for his or her documents. To make it smooth to use the blockchain and combine those technologies, the system makes use of decentralized file storage primarily based on Blockchain. Also, the databases used by this machine are FileCoin for login information and Web3 Token for document sharing and storing, which brings protection into the scene, makes storage decentralized, and increases transparency.