Bing-Yang Lin, Daria Dziubałtowska, Piotr Macek, Andreas Penzkofer · 5 authors
DAG-based DLTs allow for parallel, asynchronous writing access to a ledger. Consequently, the perception of the most recent blocks may differ considerably between nodes, and the underlying network properties of the P2P layer have a direct impact on the performance of the protocol. Moreover, the stronger inter-dependencies of several core components demand a more complex and complete approach to studying such DLTs. This paper presents an agent-based, open-sourced simulator for large-scale networks that implement the leaderless Tangle 2.0 consensus protocol. Its scope includes modelling the underlying peer-to-peer communication with network topology, package loss, heterogeneous latency, the gossip protocol with reliable broadcast qualities, the underlying DAG-based data structure, and the consensus protocol. The simulator allows us to explore the performance of the protocol in different network environments, as well as different attack scenarios.
Web3, the next generation of the Internet, represents a decentralized and democratized web. Although it has garnered significant public interest and found numerous real-world applications, there is a limited understanding of people's perceptions and experiences with Web3. In this study, we conducted an empirical study to investigate the categories of Web3 application and their popularity, as well as the potential challenges and opportunities within this emerging landscape. Our research was carried out in two phases. In the first phase, we analyzed 200 popular Web3 projects associated with 10 leading Web3 venture capital firms. In the second phase, we collected and examined code-related data from GitHub and market-related data from blockchain browsers (e.g., Etherscan) for these projects. Our analysis revealed that the Web3 ecosystem can be categorized into two groups, i.e., Web3 infrastructure and Web3 applications, with each consisting of several subcategories or subdomains. We also gained insights into the popularity of these Web3 projects at both the code and market levels and pointed out the challenges in the Web3 ecosystem at the system, developer, and user levels, as well as the opportunities it presents. Our findings contribute to a better understanding of Web3 for researchers and developers, promoting further exploration and advancement in this innovative field.
Data synchronization in decentralized storage systems is essential to guarantee sufficient redundancy to prevent data loss. We present SNIPS, the first succinct proof of storage algorithm for synchronizing storage peers. A peer constructs a proof for its stored chunks and sends it to verifier peers. A verifier queries the proof to identify and subsequently requests missing chunks. The proof is succinct, supports membership queries, and requires only a few bits per chunk. We evaluated our SNIPS algorithm on a cluster of 1000 peers running Ethereum Swarm. Our results show that SNIPS reduces the amount of synchronization data by three orders of magnitude compared to the state-of-the-art. Additionally, creating and verifying a proof is linear with the number of chunks and typically requires only tens of microseconds per chunk. These qualities are vital for our use case, as we envision running SNIPS frequently to maintain sufficient redundancy consistently.
Abstract This project aims to produce a cryptocurrency blockchain application. An online application can be accessed via this Blockchain Application System. Everyone with a net connection is able to access it throughout the Internet. This programme will assist the user in sending and receiving Ethereum over the blockchain network. A blockchain is a distributed, trustworthy data repository. Public-key cryptography and the Nobel idea are combined to make it work. The legitimate owner of the resource being traded signs each transaction on the blockchain. New currencies (resources) are created and given to an owner. Simply embed the new owner's public key in the transaction and sign it with the owner's private key to get ready for subsequent transactions that deliver those coins to other people. In this manner, a verifiable chain of transactions is established, with each new transaction linking to the previous transaction with the previous owner and having a new owner.
Open access
Blockchain Technology Applications and Security
Peer-to-Peer Network Technologies
Advanced Steganography and Watermarking Techniques
Currently, digital certificate systems based on blockchain have been extensively developed and adopted. However, most of them do not take into account the certificate quality. To evaluate the credibility of certificates issued by educational institutions, we propose a novel blockchain-based system with credit self-adjustment (BC-CS). In BC-CS, employers can provide feedback according to the performances of their employees (i.e., students) holding different certificates. Based on the feedback, BC-CS automatically adjusts the certificate credits by using our proposed credit self-adjustment algorithm. To verify the feasibility of our proposed system, a decentralized application prototype has been developed on an Ethereum network. Experimental results demonstrate that the proposed system can fully support multi-step accreditation and automatic adjustment for certificate credit.
A non-fungible token (NFT) is a data unit stored on the blockchain. Nowadays, more and more investors and collectors (NFT traders), who participate in transactions of NFTs, have an urgent need to assess the performance of NFTs. However, there are two challenges for NFT traders when analyzing the performance of NFT. First, the current rarity models have flaws and are sometimes not convincing. In addition, NFT performance is dependent on multiple factors, such as images (high-dimensional data), history transactions (network), and market evolution (time series). It is difficult to take comprehensive consideration and analyze NFT performance efficiently. To address these challenges, we propose NFTVis, a visual analysis system that facilitates assessing individual NFT performance. A new NFT rarity model is proposed to quantify NFTs with images. Four well-coordinated views are designed to represent the various factors affecting the performance of the NFT. Finally, we evaluate the usefulness and effectiveness of our system using two case studies and user studies.
We introduce semitopology, a generalisation of point-set topology that removes the restriction that intersections of open sets need necessarily be open. The intuition is that points represent participants in a decentralised system, and open sets represent collections of participants that collectively have the authority to collaborate to update their local state; we call this an actionable coalition. Examples of actionable coalition include: majority stakes in proof-of-stake blockchains; communicating peers in peer-to-peer networks; and even pedestrians working together to not bump into one another in the street. Where actionable coalitions exist, they have in common that: collaborations are local (updating the states of the participants in the coalition, but not immediately those of the whole system); collaborations are voluntary (up to and including breaking rules); participants may be heterogeneous in their computing power or in their goals (not all pedestrians want to go to the same place); participants can choose with whom to collaborate; and they are not assumed subject to permission or synchronisation by a central authority. We develop a topology-flavoured mathematics that goes some way to explaining how and why these complex decentralised systems can exhibit order, and gives us new ways to understand existing practical implementations.
For Nakamoto's longest-chain consensus protocol, whose proof-of-work (PoW) and proof-of-stake (PoS) variants power major blockchains such as Bitcoin and Cardano, we revisit the classic problem of the security--performance tradeoff: Given a network of nodes with finite communication- and computation-resources, against what fraction of adversary power is Nakamoto consensus (NC) secure for a given block production rate? State-of-the-art analyses of NC fail to answer this question, because their bounded-delay model does not capture the rate limits to nodes' processing of blocks, which cause congestion when blocks are released in quick succession. We develop a new analysis technique to prove a refined security--performance tradeoff for PoW NC in a bounded-capacity model. In this model, we show that, in contrast to the classic bounded-delay model, Nakamoto's private attack is no longer the worst attack, and a new attack we call the teasing strategy, that exploits congestion, is strictly worse. In PoS, equivocating blocks can exacerbate congestion, making traditional PoS NC insecure except at very low block production rates. To counter such equivocation spamming, we present a variant of PoS NC we call Blanking NC (BlaNC), which achieves the same resilience as PoW NC.
Currently, Gasper, the implemented consensus protocol of Ethereum, takes between 64 and 95 slots to finalize blocks. Because of that, a significant portion of the chain is susceptible to reorgs. The possibility to capture MEV (Maximum Extractable Value) through such reorgs can then disincentivize honestly following the protocol, breaking the desired correspondence of honest and rational behavior. Moreover, the relatively long time to finality forces users to choose between economic security and faster transaction confirmation. This motivates the study of the so-called single slot finality protocols: consensus protocols that finalize a block in each slot and, more importantly, that finalize the block proposed at a given slot within such slot. In this work we propose a simple, non-blackbox protocol that combines a synchronous dynamically available protocol with a partially synchronous finality gadget, resulting in a consensus protocol that can finalize one block per slot, paving the way to single slot finality within Ethereum. Importantly, the protocol we present can finalize the block proposed in a slot, within such slot.
Guzmán Llambías, Bruno Bradach, Juan J. Nogueira, Laura González · 5 authors
Blockchain is a distributed ledger technology (DLT) to manage data in a decentralised way. During the last years, interoperability has become one of the main challenges within blockchain research as blockchains increasingly require integration between each other. Indeed, blockchains work by design in silos of information as interoperability is not a native feature. The main efforts in the field are focused on blockchains, such as Bitcoin and Ethereum. However, interoperability in DLT remains as an almost untouched area of work as they introduce additional requirements focusing on privacy and identity. Although there are some interoperability solutions for DLT, they are either high-level design proposals not providing concrete implementations or focus on interoperability issues between business applications and blockchain platforms. In this paper we propose a gateway-based platform-to-platform interoperability solution for DLT, which comprises a detailed solution design and a reference implementation. The proposal was assessed through the development of a social security case scenario and the evaluation through two interoperability frameworks. A reference implementation was built using two DLT: Hyperledger Fabric and Corda. The experimental results shows that it is possible to achieve technical interoperability between two heterogeneous DLT platforms using a gateway-based interoperability solution, relaxing decentralisation, data privacy, identity and authorisation management properties.
Before the advent of alternative blockchains such as Ethereum, the future of decentralization was all in the hands of Bitcoin. Together with Nakamoto itself, early developers were trying to leverage Bitcoin potential to decentralize traditionally centralized applications. However, being Bitcoin a decentralized machine, available non-trustless oracles were considered unsuitable. Therefore, strategies had to be elaborated to solve the so-called oracle problem in the newborn scenario. By interviewing early developers and crawling early forums and repositories, this paper aims to retrace and reconstruct the chain of events and contributions that gave birth to oracles on Bitcoin. The evolution of early trust models and approaches to solving the oracle problem is also outlined. Analyzing technical and social barriers to building oracles on Bitcoin, the transition to Ethereum will also be discussed.
With the progress of the internet from web 2.0 to web 3.0, the increased use of decentralized applications has emerged. Popularized by BlockChain but not limited to decentralized finance, decentralized applications have vast applications with regards to security, storage, and delivery of content over the web. In this paper we outlines the development of a web application prototype using JavaScript programming language, JavaScript based libraries such as BugOut and PeerJS, and the WebRTC (Web Real Time Communication) framework. We have also discuss the brief comparisons between the existing centralized applications and our proposed model. An essential component of this prototype is outlined via the use of P2P networking, which is the backbone of decentralization.
The Synchronic Web is a highly scalable notary infrastructure that provides tamper-evident data provenance for historical web data. In this document, we describe the applicability of this infrastructure for web archiving across three envisioned stages of adoption. We codify the core mechanism enabling the value proposition: a procedure for splitting and merging cryptographic information fluidly across blockchain-backed ledgers. Finally, we present preliminary performance results that indicate the feasibility of our approach for modern web archiving scales.
Abstract: This paper suggests a decentralised web hosting solution based on Web3 Storage and the Interplanetary File System (IPFS). The IPFS platform is used to host websites and store data. To guarantee that the source codes of the websites and users’ data are preserved over the long term, all storage miner nodes on the IPFS network provide the pinning service. Websites must use an encryption technique for data storage that protects user privacy. The suggested model integrates the Web3 Storage and IPFS networks to create a platform that offers decentralised site hosting. The suggested platform guarantees the privacy, availability, and integrity.
Distributed Ledger Technology (DLT) allows the maintenance of a continuously growing ledger in a peer-to-peer network. Nodes participating in the network require significant computational power and memory to download and verify the ledger. To solve this problem, light clients were developed to verify the integrity of the ledger by downloading only a subset of the ledger, but they are vulnerable to malicious influence. The thesis presents Aurora, a set of three stochastic algorithms that add trustlessness to DLT networks by analyzing the network structure and discovering sets that contain honest nodes that can be used for future interactions. The solution allows a new node to join the network and initiate ledger download with an honest node, or to check the presence of a transaction without downloading the entire ledger or a subset of the ledger. The work provides a comprehensive overview of DLT, pseudocode for the solution, and an evaluation procedure using open-source DLT simulation tools. Furthermore, the solution was integrated into Trinity, a Python-based DLT client for the Ethereum network, and was evaluated on the Ethereum production network, consuming approximately 0.31 MB of RAM and 1 MB of storage at runtime. The proposed solution outperforms other state-of-the-art solutions and can be deployed on resource-constrained devices. It incentivizes users to interact with the ledger in a trustless manner. Overview of scientific contribution: 1. A new probabilistic honest set creation algorithm 2. A new probabilistic transaction history synchronization algorithm 3. A new probabilistic transaction presence checking algorithm 4. A new evaluation procedure in a resource constrained environment
Lucian Trestioreanu, Wazen M. Shbair, Flaviene Scheidt de Cristo, Radu State
With the growing adoption of Distributed Ledger Technologies and the subsequent scaling of these networks, there is an inherent need for efficient and resilient communication used by the underlying consensus and replication mechanisms. While resilient and efficient communication is one of the main pillars of an efficient blockchain network as a whole, the Distributed Ledger Technology is still relatively new and the task of scaling these networks has come with its own challenges towards ensuring these goals. New content distribution concepts like Information Centric Networking, of which Named Data Networking is a worthy example, create new possibilities towards achieving this goal, through in-network caching or built-in native multicasting, for example. We present and evaluate XRP-NDN Overlay, a solution for increasing the communication efficiency for consensus-validation based blockchains like the XRP Ledger. We experiment by sending the XRP Ledger consensus messages over different Named Data Networking communication models and prove that our chosen model lowers the number of messages at node level to minimum necessary, while maintaining or improving blockchain performance by leveraging the possibilities offered by an overlay such as specific communication mechanisms.
Blockchain and other distributed ledger technologies have enabled peer-to-peer networks to maintain ledgers with an immutable history and guaranteed computation, all carried out without the need of trusted parties. In practice, few applications of blockchain are closed i.e. do not interact with the world outside the blockchain, and various techniques have been proposed and used to handle such interaction. One problem is that it is widely accepted that, due to the decentralised nature of blockchain networks and constraints to ensure trust and determinism, such communication can only flow into the blockchain, and that blockchain systems cannot initiate and execute calls to external systems or services. In this paper we show that this misconception is preconceived by building on our previously presented solution to demonstrate that such calls can be directly initiated from the blockchain itself in a feasible and efficient manner.
The network formation process in the Bitcoin protocol is designed to hide the global network structure: while most of the nodes of the network can be easily discovered, the existence of an edge between two nodes is only known by the two endpoints. In [Becchetti et al., SODA2020] the authors propose a dynamic random graph model inspired by the network formation process in the Bitcoin protocol and they prove that the evolution of the graph quickly terminates and that the resulting graph is an expander, with high probability.
Blockchains can provide integrity and authenticity, but their limited storage capacity can be a challenge when it comes to storing large amounts of data. To address this issue, off-chain storage solutions such as the InterPlanetary File System (IPFS) can be utilized. This has led to the emergence of various applications that utilize both blockchain and IPFS. After reviewing a large body of literature utilizing blockchain and IPFS, we found that the coordinated interaction between blockchain and IPFS can help solve many problems and provide many research opportunities. Therefore, this survey paper aims to introduce the interaction mechanism between blockchain and IPFS. We first provide a general overview and comparison of different P2P data networks to help understand why IPFS is suitable as the storage layer for blockchains. Subsequently, we use select applications that leverage blockchain and IPFS to show how the mechanism works and explore new developments in this area. Specifically, we identify research areas and provide a qualitative comparison of these different applications. From the comparison, we derive research goals related to the interaction mechanism between blockchain and IPFS.
Decentralized Finance (DeFi) continues to open up promising opportunities for a broad spectrum of users, with lending pools emerging as a cornerstone of its applications. While prominent platforms like Compound and Aave maintain a large share of the funds in lending pools, numerous other smaller pools also exist. Many of these smaller entities draw heavily from the design principles of their larger counterparts due to the complex nature of lending pool design. This paper asserts that the design approaches that serve larger pools effectively may not necessarily be the most beneficial for smaller lending pools. We identify and elaborate on two liquidity management attacks, which can allow well-funded attackers to exploit specific circumstances within lending pools for personal gain. Although large lending pools, due to their vast and diverse liquidity and high user engagement, are generally less vulnerable to these attacks, smaller lending protocols may need to employ specialized defensive strategies, particularly during periods of low liquidity. We also show that beyond the six leading lending protocols, there exists a market value exceeding $1.75 billion. This considerable sum is dispersed among over 200 liquidity pools, posing a potentially attractive target for bad actors. Furthermore, we evaluate existing designs of lending pools and suggest a novel architecture that distinctly separates the liquidity and logic layers. This unique setup gives smaller pools the adaptability they need to link with larger, well-established pools. Despite encountering certain constraints, these emerging pools can leverage the considerable liquidity from larger pools until they generate sufficient funds to form their own standalone liquidity pools. This design cultivates a setting where multiple lending pools can integrate their liquidity components, thus encouraging a more diverse and robust liquidity environment.
Multimedia networking is the area of study associated with the delivery of heterogeneous data including, but not limited to, imagery, video, audio, and interactive content. Multimedia and communication network researchers have continually struggled to devise solutions for addressing the three core challenges in multimedia delivery: security, reliability, and performance. Solutions to these challenges typically exist in a spectrum of compromises achieving gains in one aspect at the cost of one or more of the others. Networked videogames represent the pinnacle of multimedia presented in a real-time interactive format. Continual improvements to multimedia delivery have led to tools such as buffering, redundant coupling of low-resolution alternative data streams, congestion avoidance, and forced in-order delivery of best-effort service; however, videogames cannot afford to pay the latency tax of these solutions in their current state. The Secure Multi-Channel Internet Memory Information Control (S-MIMIC) protocol was developed as a novel solution to address these challenges by leveraging recent developments in blockchain and distributed ledger technology. Multiple algorithms were developed within the S-MIMIC protocol to perform create, read, update, and delete (CRUD) interactions via distributed ledger and blockchain technologies. Performance of the the S-MIMIC protocol was evaluated by porting its capabilities into an open source First-Person Shooter (FPS) videogame developed within the Unity3D game engine. SMIMIC efficacy was evaluated across the dimensions of confidentiality, integrity, availability and read/write performance. Though performance evaluation of the S-MIMIC focused on implementation within videogames, this protocol may be used to augment data delivery in multiple industries to include: medical information, legal documents, financial transactions, and many other applications that require security, reliability and performance guarantees.
Different from “read” based Web1 and “read-write” based Web2, “read-write-own” based Web3 is proposed as a typical user-centric internet to open the new generation of World Wide Web, which is expected to not allow the power to rest with a few big internet companies. Generally, Web3 is decentralized and semantic depending on user behavior, and thus the zero-trust architecture should be created initially. To hasten its arrival, a comprehensive discussion on its architecture and enabling technologies is inspired. Specifically, to access Web3, it is essential to study how to establish an identity management system. Meanwhile, for resource description and data verification, it is necessary to set up decentralized identifiers (DID), and link the data to identifiers in the form of DID document. In particular, a decentralized network operating system is an indispensable underlying technology for Web3, incorporating concepts such as decentralization and user-driven philosophy. Therefore, the corresponding technologies for the operating system such as blockchain and distributed ledger technology should be further studied and developed. Moreover, in order to reduce the consensus cost, a large-scale incentive mechanism is also the basis of long-term sustainability, which can attract and motivate distributed players to participate in the maintenance of Web3. Last but not the least, Web3 is built on a physical infrastructure relying on communication, networking, storage and computing, which is crucial to establishing an effective and secure Web3. This encourages us to study communication, networking, storage and computing in Web3, as well as the specific requirements of running Web3.