Blockchain Papers

Mikołaj Barczentewicz

No abstract is available for this record.

Apurba Pokharel, Krishna Dahal

No abstract is available for this record.

B. Suresh Kumar Shetty

Data sharing is a crucial step in the research community to make the most of the prior effort. Platforms for sharing data currently in use rely on trustworthy third parties (TTP). Such systems lack immutability, security, transparency, and trust because of TTP’s involvement. In order to address these problems, the proposed system approaches an Interplanetary File System (IPFS)-based blockchain-based secure data sharing platform. The user uploads a data file to the IPFS server, which is subsequently split up into several secret shares. By carrying out the access responsibilities that the user has specified in the smart contract, the suggested scheme accomplishes security and access control. This scenario combines encryption, Ethereum blockchain technology, decentralized storage, and incentive systems. Solidity smart contracts are created and deployed on a local Ethereum test network in order to carry out the suggested scenario. Transparency, Security, Access control, Owner authenticity, and Data quality are all achieved by the suggested plan.

Denis Avrilionis, Thomas Hardjono

Today there is considerable interest in deploying blockchains and\ndecentralized ledger technology as a means to address the deficiencies of\ncurrent financial and digital asset infrastructures. The focal point of\nattention in many projects on digital asset and cryptocurrency is centered\naround blockchain systems and smart contracts. Many projects seek to make the\nblockchain as the centerpiece of the new decentralized world of finance.\nHowever, several roadblocks and challenges currently face this predominant\nblockchain-centric view. In this paper we argue that the proper and correct\nperspective on decentralized economy should be one that is asset-centric, where\nthe goal should be the consistent lifecycle management of assets in the\nreal-world with their digital representation on the blockchain. We introduce\nthe notion of the digital twin to capture the relationship between a real-world\nasset and its on-chain representation. A digital twin container is utilized to\npermit off-chain state persistence and on-chain state traceability, where the\ncontainer can be deployed on the blockchain as well as on traditional\napplication servers. The digital twin container becomes the bridge between\nlegacy infrastructures and the newly emergent blockchain infrastructures,\npermitting legacy systems to interoperate consistently with blockchain systems.\nWe believe this asset-centric view to be the correct evolutionary direction for\nthe nascent field of blockchains and decentralized ledger technology.\n

Viraaji Mothukuri, Sai S. Cheerla, Reza M. Parizi, Qi Zhang · 5 authors

Hadoop Distributed File System (HDFS) is one of the widely used distributed file systems in big data analysis for frameworks such as Hadoop. HDFS allows one to manage large volumes of data using low-cost commodity hardware. However, vulnerabilities in HDFS can be exploited for nefarious activities. This reinforces the importance of ensuring robust security to facilitate file sharing in Hadoop as well as having a trusted mechanism to check the authenticity of shared files. This is the focus of this paper, where we aim to improve the security of HDFS using a blockchain-enabled approach (hereafter referred to as BlockHDFS). Specifically, the proposed BlockHDFS uses the enterprise-level Hyperledger Fabric platform to capitalize on files' metadata for building trusted data security and traceability in HDFS.

Isaac Adjei-Mensah, Isaac Osei Agyemang, Collins Sey, Linda Delali Fiasam · 5 authors

From online education and trading, all aspects of our lives are affected by digital technology. Among them, the storage of music has also entered the digital era. Music productions created by artists have brought great joy to people. However, when artists upload their works, they are most downloaded and reprinted by others, and copyright information and the issue associated with the sharing of music arise. This will have a significant negative impact on the enthusiasm and motivation of artists. This paper provides an internet database platform for artists, which uses the distributed and tamper-proof technology of the Ethereum blockchain to store music works, and protect the copyright information of each album or music produced by artists in the music industry. Design and implementation of the system model and data storage are proposed and data storage processes based on the Ethereum smart contract are demonstrated in detail. The system stores music information on the blockchain network, using the smart contract to provide artists with a fast and efficient royalty payment. Node.js is applied to carry out the experiments of our system, and we test Remote Procedure Calls (RPC) with available account and private keys for contract development and use block explorer to track music information on the blockchain. Our system enables copyright revenue to be attributed to music creators that will help to eliminate the illegal uploading of music on other websites.

K N Devika, Ramesh Bhakthavatchalu

This paper concentrates on the hardware implementation of efficient and re- configurable elliptic curve digital signature algorithm (ECDSA) that is suitable for verifying transactions in Blockchain related applications. Despite ECDSA architecture being computationally expensive, the usage of a dedicated stand-alone circuit enables speedy execution of arithmetic operations. The prototype put forth supports N-bit elliptic curve cryptography (ECC) group operations, signature generation and verification over a prime field for any elliptic curve. The research proposes new hardware framework for modular multiplication and modular multiplicative inverse which is adopted for group operations involved in ECDSA. Every hardware design offered are simulated using modelsim register transfer logic (RTL) simulator. Field programmable gate array (FPGA) implementation of var- ious modules within ECDSA circuit is compared with equivalent existing techniques that is both hardware and software based to highlight the superiority of the suggested work. The results showcased prove that the designs implemented are both area and speed efficient with faster execution and less resource utilization while maintaining the same level of security. The suggested ECDSA structure could replace the software equivalent of digital signatures in hardware blockchain to thwart software attacks and to provide better data protection.

MohammadAmin Fazli, Ali Owfi, Mohammad Reza Taesiri

Non Fungible Tokens (NFTs) have gained a solid foothold within the crypto community, and substantial amounts of money have been allocated to their trades. In this paper, we studied one of the most prominent marketplaces dedicated to NFT auctions and trades, Foundation. We analyzed the activities on Foundation and identified several intriguing underlying dynamics that occur on this platform. Moreover, We performed social network analysis on a graph that we had created based on transferred NFTs on Foundation, and then described the characteristics of this graph. Lastly, We built a neural network-based similarity model for retrieving and clustering similar NFTs. We also showed that for most NFTs, their performances in auctions were comparable with the auction performance of other NFTs in their cluster.

Andreas Zeiselmair, Bernd Steinkopf, Ulrich Gallersdörfer, Alexander Bogensperger · 5 authors

The energy system is becoming increasingly decentralized. This development requires integrating and coordinating a rising number of actors and small units in a complex system. Blockchain could provide a base infrastructure for new tools and platforms that address these tasks in various aspects—ranging from dispatch optimization or dynamic load adaption to (local) market mechanisms. Many of these applications are currently in development and subject to research projects. In decentralized energy markets especially, the optimized allocation of energy products demands complex computation. Combining these with distributed ledger technologies leads to bottlenecks and challenges regarding privacy requirements and performance due to limited storage and computational resources. Verifiable computation techniques promise a solution to these issues. This paper presents an overview of verifiable computation technologies, including trusted oracles, zkSNARKs, and multi-party computation. We further analyze their application in blockchain environments with a focus on energy-related applications. Applied to a distinct optimization problem of renewable energy certificates, we have evaluated these solution approaches and finally demonstrate an implementation of a Simplex-Optimization using zkSNARKs as a case study. We conclude with an assessment of the applicability of the described verifiable computation techniques and address limitations for large-scale deployment, followed by an outlook on current development trends.

Christos Chrysoulas, A. M. Thomson, Nikolaos Pitropakis, Pavlos Papadopoulos · 10 authors

The continuously advancing digitization has provided answers to the bureaucratic problems faced by eGovernance services. This innovation led them to an era of automation it has broadened the attack surface and made them a popular target for cyber attacks. eGovernance services utilize internet, which is currently a location addressed system where whoever controls the location controls not only the content itself, but the integrity of that content, and the access to that content. We propose GLASS, a decentralised solution which combines the InterPlanetary File System (IPFS) with Distributed Ledger technology and Smart Contracts to secure EGovernance services. We also create a testbed environment where we measure the IPFS performance.

Dimitri Saingre, Thomas Ledoux, Jean-Marc Menaud

Smart contracts, scripts at the heart of blockchain-based applications, are meant to be available forever once deployed. However, this property has a price. The amount of space required to store new contracts keeps increasing. This increase impacts each participating node's performance and makes it inconvenient for low-end devices to participate in the network. Among all contracts deployed in the blockchain, a vast majority will lead to little if any usage. We demonstrate that, in the course of one year, 70 % of deployed contracts lead to no use. Unfortunately, unused contracts keep occupying space on the blockchain. To tackle this issue, we propose a new protocol to identify and delete unused contracts. Through simulation, based on Ethereum historical data, we show that deletion of smart contracts after an inactivity period of 90 days could lead to a 66 % reduction in the number of contracts stored over a year.

Kamil Ježek

Ethereum platform operates with rich spectrum of data structures and hashing and coding functions. The main source describing them is the Yellow paper, complemented by a lot of informal blogs. These sources are somehow limited. In particular, the Yellow paper does not ideally balance brevity and detail, in some parts it is very detail, while too shallow elsewhere. The blogs on the other hand are often too vague and in certain cases contain incorrect information. As a solution, we provide this document, which summarises data structures used in Ethereum. The goal is to provide sufficient detail while keeping brevity. Sufficiently detailed formal view is enriched with examples to extend on clarity.

Ghada Almashaqbeh, Fabrice Benhamouda, Seungwook Han, Daniel Jaroslawicz · 9 authors

Abstract Existing models for non-interactive MPC cannot provide full privacy for inputs, because they inherently leak the residual function (i.e., the output of the function on the honest parties’ input together with all possible values of the adversarial inputs). For example, in any non-interactive sealed-bid auction, the last bidder can figure out what was the highest previous bid. We present a new MPC model which avoids this privacy leak. To achieve this, we utilize a blockchain in a novel way, incorporating smart contracts and arbitrary parties that can be incentivized to perform computation (“bounty hunters,” akin to miners). Security is maintained under a monetary assumption about the parties: an honest party can temporarily supply a recoverable collateral of value higher than the computational cost an adversary can expend. We thus construct non-interactive MPC protocols with strong security guarantees (full security, no residual leakage) in the short term. Over time, as the adversary can invest more and more computational resources, the security guarantee decays. Thus, our model, which we call Gage MPC, is suitable for secure computation with limited-time secrecy, such as auctions. A key ingredient in our protocols is a primitive we call “Gage Time Capsules” (GaTC): a time capsule that allows a party to commit to a value that others are able to reveal but only at a designated computational cost. A GaTC allows a party to commit to a value together with a monetary collateral. If the original party properly opens the GaTC, it can recover the collateral. Otherwise, the collateral is used to incentivize bounty hunters to open the GaTC. This primitive is used to ensure completion of Gage MPC protocols on the desired inputs. As a requisite tool (of independent interest), we present a generalization of garbled circuit that are more robust: they can tolerate exposure of extra input labels. This is in contrast to Yao’s garbled circuits, whose secrecy breaks down if even a single extra label is exposed. Finally, we present a proof-of-concept implementation of a special case of our construction, yielding an auction functionality over an Ethereum-like blockchain.

Hrvoje Stančić, Vladimir Bralić

Archives, both analogue and digital, are primarily concerned with preserving records as originals. Because of this, immutable data as used in a blockchain data structure seem a logical choice when designing such systems. At the same time, archives maintain records which may need to change over the long term. It is a requirement of archival preservation to be able to update records’ metadata in order not only to guarantee authenticity after digital preservation actions but also to ensure that relationships to other records, which might be created after an original record has entered the archive (and has been registered in a blockchain), can be maintained. The need to maintain an archival bond, which represents a network of relationships between aggregation of records, i.e., the relationship connecting previous and subsequent records belonging to the same activity, is a prime example of this requirement. This paper explores realisation of the archival bond in the context of blockchain-based archival system by proposing a supporting database system which enables metadata to be changed as required but also significantly simplifies searching compared to searching on-chain information, while keeping the immutability characteristic of blockchain.

Cosimo Laneve, Claudio Sacerdoti Coen

We define a technique for analyzing updates of smart contracts balances due to transfers of digital assets. The analysis addresses a lightweight smart contract language and consists of a two-step translation. First, we define the input-output behaviors of smart contract functions by means of a simple functional language with static dispatch. Then we associate the terms of this intermediate language with cost equations that compute the loss or gain of digital assets. The resulting equations can be fed to an off-the-shelf cost analyzer to provide upper bounds to the loss or gain. Our analysis has been prototyped and we report its assessments and discuss extensions with additional features.

Simon Cousaert, Jiahua Xu, Toshiko Matsui

Yield farming has been an immensely popular activity for cryptocurrency holders since the explosion of Decentralized Finance (DeFi) in the summer of 2020. In this Systematization of Knowledge (SoK), we study a general framework for yield farming strategies with empirical analysis. First, we summarize the fundamentals of yield farming by focusing on the protocols and tokens used by aggregators. We then examine the sources of yield and translate those into three example yield farming strategies, followed by the simulations of yield farming performance, based on these strategies. We further compare four major yield aggregrators -- Idle, Pickle, Harvest and Yearn -- in the ecosystem, along with brief introductions of others. We systematize their strategies and revenue models, and conduct an empirical analysis with on-chain data from example vaults, to find a plausible connection between data anomalies and historical events. Finally, we discuss the benefits and risks of yield aggregators.

Alex Shamis, Peter Pietzuch, Miguel Castro, Edward Ashton · 12 authors

Permissioned ledger systems execute transactions on a set of replicas governed by members of a consortium. They use Byzantine fault tolerance protocols to distribute trust among the replicas, and thus can ensure linearizability if fewer than 1/3 of the replicas misbehave. With more misbehaving replicas, current systems provide no guarantees, and all replicas and members share the blame. We describe PAC, a permissioned ledger system that \emph{assigns blame to misbehaving replicas} while supporting \emph{governance transactions} to change the consortium membership and the set of replicas. PAC signs and stores protocol messages in the ledger and provides clients with signed, universally-verifiable \emph{receipts} as evidence that a transaction executed at a certain ledger position. If clients obtain a sequence of receipts that violate linearizability, anyone can \emph{audit} the ledger and the sequence of receipts to assign blame to at least 1/3 of the replicas, even if all replicas and members misbehave. Auditing assigns blame by finding contradictory statements signed by the same replica. Since the set of replicas changes, PAC determines the valid signing keys at any point in the ledger using a shorter sub-ledger of governance transactions. PAC provides a strong disincentive to misbehavior at low cost: it can execute more than 48,000~transactions per second, and clients receive receipts in two network round trips.

Zihan Zheng, Peichen Xie, Xian Zhang, Shuo Chen · 9 authors

Smart contract is one of the core features of Ethereum and has inspired many blockchain descendants. Since its advent, the verification paradigm of smart contract has been improving toward high scalability. It shifts from the expensive on-chain verification to the orchestration of off-chain VM (virtual machine) execution and on-chain arbitration with the pinpoint protocol. The representative projects are TrueBit, Arbitrum, YODA, ACE, and Optimism. Inspired by visionaries in academia and industry, we consider the DNN computation to be promising but on the next level of complexity for the verification paradigm of smart contract. Unfortunately, even for the state-of-the-art verification paradigm, off-chain VM execution of DNN computation has an orders-of-magnitude slowdown compared to the native off-chain execution. To enable the native off-chain execution of verifiable DNN computation, we present Agatha system, which solves the significant challenges of misalignment and inconsistency: (1) Native DNN computation has a graph-based computation paradigm misaligned with previous VM-based execution and arbitration; (2) Native DNN computation may be inconsistent cross platforms which invalidates the verification paradigm. In response, we propose the graph-based pinpoint protocol (GPP) which enables the pinpoint protocol on computational graphs, and bridges the native off-chain execution and the contract arbitration. We also develop a technique named Cross-evaluator Consistent Execution (XCE), which guarantees cross-platform consistency and forms the correctness foundation of GPP. We showcase Agatha for the DNN computation of popular models (MobileNet, ResNet50 and VGG16) on Ethereum. Agatha achieves a negligible on-chain overhead, and an off-chain execution overhead of 3.0%, which represents an off-chain latency reduction of at least 602x compared to the state-of-the-art verification paradigm.

Hazay, Carmit, Venkitasubramaniam, Muthuramakrishnan, Weiss, Mor

Leakage-resilient cryptography aims to protect cryptographic primitives from so-called "side channel attacks" that exploit their physical implementation to learn their input or secret state. Starting from the works of Ishai, Sahai and Wagner (CRYPTO`03) and Micali and Reyzin (TCC`04), most works on leakage-resilient cryptography either focus on protecting general computations, such as circuits or multiparty computation protocols, or on specific non-interactive primitives such as storage, encryption and signatures. This work focuses on leakage-resilience for the middle ground, namely for distributed and interactive cryptographic primitives. Our main technical contribution is designing the first secret-sharing scheme that is equivocal, resists adaptive probing of a constant fraction of bits from each share, while incurring only a constant blowup in share size. Equivocation is a strong leakage-resilience guarantee, recently introduced by Hazay et al. (ITC`21). Our construction is obtained via a general compiler which we introduce, that transforms any secret-sharing scheme into an equivocal scheme against adaptive leakage. An attractive feature of our compiler is that it respects additive reconstruction, namely, if the original scheme has additive reconstruction, then the transformed scheme has linear reconstruction. We extend our compiler to a general paradigm for protecting distributed primitives against leakage, and show its applicability to various primitives, including secret sharing, verifiable secret sharing, function secret sharing, distributed encryption and signatures, and distributed zero-knowledge proofs. For each of these primitives, our paradigm transforms any construction of the primitive into a scheme that resists adaptive party corruptions, as well as adaptive probing leakage of a constant fraction of bits in each share when the share is stored in memory (but not when it is used in computations). Moreover, the transformation incurs only a constant blowup in the share size, and respects additive reconstruction - an important feature for several of these primitives, such as function secret sharing and distributed encryption.

Shashikant Patil, Smita Nirkhi

<strong>The most accepted cryptographic money is the bitcoin, which is highly attracting the traders and investors for making buy or sell decisions. However, the prediction of the bitcoin prices is challenging due to its higher voltality. In this work, a new bitcoin prediction model is introduced with three major phases: Pre-processing, Feature Extraction and Prediction. The collected bit coin data corresponding to minute-by-minute and hour-by-hour data is subjected to pre-processing. From the pre-processed data, the original features are extracted along with the features based on technical indicators. Average True Range (ATR), Exponential Moving Average (EMA) and Relative Strength Index (RSI) are the technical indicators computed. All the extracted features are subjected to prediction phase, where the optimized Neural Network (NN) model is used. To make the prediction more accurate, the training of NN is carried out by the renowned Elephant Herding Optimization (EHO) via tuning the weight. Finally, the algorithmic analysis is carried out by varying the window size.</strong>

Ang Jia, Ming Fan, Xi Xu, Di Cui · 8 authors

The great influence of Bitcoin has promoted the rapid development of blockchain-based digital currencies, especially the altcoins, since 2013. However, most altcoins share similar source codes, resulting in concerns about code innovations. In this paper, an empirical study on existing altcoins is carried out to offer a thorough understanding of various aspects associated with altcoin innovations. Firstly, we construct the dataset of altcoins, including source code repositories, GitHub fork relations, and market capitalizations (cap). Then, we analyze the altcoin innovations from the perspective of source code similarities. The results demonstrate that more than 85% of altcoin repositories present high code similarities. Next, a temporal clustering algorithm is proposed to mine the inheritance relationship among various altcoins. The family pedigrees of altcoin are constructed, in which the altcoin presents similar evolution features as biology, such as power-law in family size, variety in family evolution, etc. Finally, we investigate the correlation between code innovations and market capitalization. Although we fail to predict the price of altcoins based on their code similarities, the results show that altcoins with higher innovations reflect better market prospects.

Aritra Mitra

Since the advent of Bitcoin in 2008, the interest in blockchain technology has surged tremendously. Numerous applications have been proposed in the field of finance, healthcare, and supply chain over the last decade. And, as the popularity of blockchains continue to rise, blockchain platforms must be enhanced to support new application needs.&#13;\nWe propose one such enhancement that is essential for financial applications and online marketplaces – support for time-based logic. Online marketplaces may need to validate transaction time-stamps against a perishable product’s expiry date to prevent sale of expired products. Similarly, financial applications in banking may also need a history of recent transactions for extending credit (like an overdraft) to a customer. As nodes in a blockchain operate in a distributed and trustless setting, it is imperative that they can access a global and trusted clock for verifying deadlines or examining a window of recent activity.&#13;\nIn this thesis, we present a lightweight solution that assigns time-stamps to blocks at transaction validation time, which can be referenced as a global clock by all nodes in the network. Moreover, our solution also maintains a cache&#13;\nreflecting the effects of recent transactions. We implement our solution, called TimeFabric, in Hyperledger Fabric, a popular permissioned blockchain platform, and experimentally demonstrate high throughput and minimal overhead (approximately 3%) of maintaining trusted time. We also demonstrate a 2x performance improvement due to the cache, compared to retrieving transaction histories directly from the ledger.

Cheman Shaik

Presented herein is a User-SpecificKey Scheme based on Elliptic Curve Cryptography that defeats man-inthe-middle attacks on cryptocurrency exchange accounts. In this scheme, a separate public and private key pair is assigned to every account and the public key is shifted either forward or backward on the elliptic curve by a difference of the account user’s password. When a user logs into his account, the server sends the shifted public key of his account. The user computes the actual public key of his account by reverse shifting the shifted public key exactly by a difference of his password. Alternatively, shifting can be applied to the user’s generator instead of the public key. Described in detail is as to how aman-in-the-middle attack takes place and how the proposed scheme defeats the attack. Provided detailed security analysis in both the cases of publickey shifting and generator shifting. Further, compared the effectiveness of another three authentication schemes in defending passwords against MITM attacks.

Syed Muhammad Sajjad Rizvi

Big data applications put significant latency and throughput demands on distributed storage systems. Meeting these demands requires storage systems to use a significant amount of infrastructure resources, such as network capacity and storage devices. Resource demands largely depend on the workloads and can vary significantly over time. Moreover, demand hotspots can move rapidly between different infrastructure locations.&#13;\n&#13;\nExisting storage systems are largely infrastructure-oblivious as they are designed to support a broad range of hardware and deployment scenarios. Most only use basic configuration information about the infrastructure to make important placement and routing decisions. In the case of cloud-based storage systems, cloud services have their own infrastructure-specific limitations, such as minimum request sizes and maximum number of concurrent requests. By ignoring infrastructure-specific details, these storage systems are unable to react to resource demand changes and may have additional inefficiencies from performing redundant network operations. As a result, provisioning enough resources for these systems to address all possible workloads and scenarios would be cost prohibitive.&#13;\n&#13;\nThis thesis studies the performance problems in commonly used distributed storage systems and introduces novel infrastructure-aware design methods to improve their performance. First, it addresses the problem of slow reads due to network congestion that is induced by disjoint replica and path selection. Selecting a read replica separately from the network path can perform poorly if all paths to the pre-selected endpoints are congested. Second, this thesis looks at scalability limitations of consensus protocols that are commonly used in geo-distributed key value stores and distributed ledgers. Due to their network-oblivious designs, existing protocols redundantly communicate over highly oversubscribed WAN links, which poorly utilize network resources and limits consistent replication at large scale. Finally, this thesis addresses the need for a cloud-specific realtime storage system for capital market use cases. Public cloud infrastructures provide feature-rich and cost-effective storage services. However, existing realtime timeseries databases are not built to take advantage of cloud storage services. Therefore, they do not effectively utilize cloud services to provide high performance while minimizing deployment cost.&#13;\n&#13;\nThis thesis presents three systems that address these problems by using infrastructure-aware design methods. Our performance evaluation of these systems shows that infrastructure-aware design is highly effective in improving the performance of large scale distributed storage systems.