Abstract Coin selection method refers to the process undergone when selecting a set of unspent transaction outputs (UTXOs) from a cryptocurrency wallet or account to use as inputs in each transaction. The most applied coin selection method that UTXO-based cryptocurrencies currently employ is an algorithm that decides on a certain set of UTXOs that matches the target amount and limits the transaction fee. However this approach trades off favourable maintenance overhead of the entire network for low transaction fees, as many low-value UTXOs known as âdustâ is produced. Over time, this will impact the scalability and management of the cryptocurrency network as the global set of UTXOs become larger. Therefore, there is an urgency to find a higher-performing coin selection method suitable for UTXO-based cryptocurrencies. This paper proposes a method based on the greedy and genetic algorithm for effectively choosing sets of UTXOs in Bitcoin. The main objective of this coin selection strategy is to get as close as possible to the target while also maintaining and possibly reducing the number of UTXO inputs.
This perspective highlights some recent progress on the research of Byzantine fault tolerant (BFT) consensus protocol in the era of blockchains, including both partially synchronous BFT and asynchronous BFT protocols, their fundamental building blocks, and their variants.
Under the current national network environment, anyone can participate in publishing. As an important information resource, knowledge files reflect the workload of publishers. Moreover, high-quality knowledge files can promote the progress of society. However, pirated inferior files have the opposite effect. At present, most organizations use centralized servers to centrally manage the knowledge files released by users. In addition, it is necessary to introduce an untrusted third party to examine and encrypt the contents of files, which leads to an opaque process of file storage transactions, tampering with intellectual copyright, and the inability to have consistent systems of file management among institutions due to the lack of uniform standards for the same intellectual files. The purpose of this paper is to ensure the safe storage of knowledge files on the one hand and to realize efficient sharing of copyrighted files on the other hand. Therefore, this paper combines NDN (Named Data Network) technology with a distributed blockchain and an Interplanetary File System (IPFS) and proposes a blockchain knowledge file storage and sharing method based on an NDN. The method uses the NDN itself for the file content signature and encryption, thereby separating the file security and transmission process. At the same time, the method uses a flexible NDN reverse path forwarding and routing strategy, combining an IPFS private storage network to improve the safety of the encrypted data storage security. Finally, the method takes advantage of all participating nodes consensus and shares files in the synchronized blockchain to ensure traceability. This paper introduces the structure and principles of the method and describes the process of file upload and transfer. Finally, the performance of the method is compared and evaluated, and the advantages and disadvantages of the method and the future research direction are summarized.
Ilya Grishkov, Roland Kromes, Thanassis Giannetsos, Kaitai Liang
This paper offers a prototype of a Hyperledger Fabric-IPFS based network architecture including a smart contract based encryption scheme that meant to improve the security of user's data that is being uploaded to the distributed ledger. A new extension to the self-encryption scheme was deployed by integrating data owner's identity into the encryption process. Such integration allows to permanently preserve ownership of the original file and link it to the person/entity who originally uploaded it. Moreover, self-encryption provides strong security guarantees that decryption of a file is computationally not feasible under the condition that the encrypted file and the key are safely stored.
With the development of blockchain applications, the requirements for file storage in blockchain are increasing rapidly. Many protocols, including Filecoin, Arweave, and Sia, have been proposed to provide scalable decentralized file storage for blockchain applications. However, the reliability is not well promised by existing protocols. Inspired by the idea of insurance, we innovatively propose a decentralized file storage protocol in blockchain, named as FileInsurer, to achieve both scalability and reliability. While ensuring scalability by distributed storage, FileInsurer guarantees reliability by enhancing robustness and fully compensating for the file loss. Specifically, under mild conditions, we prove that no more than 0.1\% value of all files should be compensated even if half of the storage collapses. Therefore, only a relatively small deposit needs to be pledged by storage providers to cover the potential file loss. Because of lower burdens of deposit, storage providers have more incentives to participate in the storage network. FileInsurer can run in the top layer of the InterPlanetary File System (IPFS), and thus it can be directly applied in Web 3.0, Non-Fungible Tokens, and Metaverse.
Alexander Pfeiffer, Natalie Denk, Thomas Wernbacher, Stephen Bezzina ¡ 6 authors
Non-Fungible Tokens (NFTa) can either represent an original digital artwork, or act as a digital reference to the actual work. In both as digital references to the actual work. In both cases the record in the distributed ledger, mostly a blockchain-based database, intends to serve as a proof of ownership or transfer of rights. NFTs might also add a further purpose, which in blockchain terms is referred to as âa utility", such as access to special websites, chats or clubs in emerging metaverse platforms. This use-case paper presents a first introduction of two early stage demonstrators, set outside the common use of art images or images of historical events as NFTs. The first case shows how educational credentials can be created, in which different teachers contribute to assessment achievements. We elaborate how these partial achievements are verified separately within the actual credentials. In the second case study, we build on previous research in regard to NFTs in the music industry and show the combination of physical vinyl record special editions, in our case vinyls signed by the band, and the ownership certificate as NFT. For both demonstrators we used, in different settings, the crypto art platform NFTmagic and the blockchain-token wallet Sigbro. We developed and tested the results within the setting of a roleplay as a group and show how blockchain technologies and especially NFTs can be made useful in new ways, inspired by the ongoing process of discovering risks and opportunities in âcrypto artâ, thus initiating discussion on the topic and effectively bridging the cybersecurity and (digital) art communities.
The embrace of cryptocurrencies by institutional investors is well underway. The futures market has already had a significant impact on this industry. Digital asset exposure may go up while the risk of loss is reduced by using derivatives. Decentralized finance and crypto-derivative trading are the focus of this article. We analyzed the function of a central clearing house (C.C.P.) and Exchange for Derivatives, especially Cryptocurrency derivatives. We mapped some critical attributes of DeFi (Decentralized Finance) to the concept of decentralized Exchange. In the light of this analysis, we reviewed an existing Cryptocurrency derivatives exchange that is trying to become a decentralized exchange. We studied dYdX, a major decentralized crypto-derivative exchange. We assessed its core purpose as a crypto-derivative exchange to investigate the positive aspects of the D.C.E. (Decentralized Crypto-derivative exchange). Decentralized crypto-derivative exchanges have considerable problems in terms of liquidity and market-making, and we determined that different incentive schemes by these exchanges have successfully overcome these issues. By linking additional trading nodes and boosting the trust of traders and investors, we believe these exchanges may be made more efficient.
Non-fungible tokens (NFTs) are transferrable rights to digital assets, such as images, videos, or music. The phenomenon and its markets have grown significantly since early 2021. The number of NFT marketplaces has been rising continuously since a couple of years. Majority of them employ centralized systems for storage of digital assets (files). This is contradictory to the notion of decentralized systems. In this project we propose a secure platform for trading digital assets in the form of Non-Fungible tokens. It will enable the users to create new digital assets and trade them in exchange of Ethereum-based cryptocurrency. Along with this, we aim to explore technical feasibility of a decentralized file system (using IPFS protocol) for storing the digital assets in a more secured way. In this way, we attempt to address the issue of file storage. Also, this project is an attempt to advocate the use of block chain technology.
Non-fungible tokens have been a unique transformation in the implementation of the concept of distributed ledger technology in digital assets. NFTs are said to be non-interchangeable, which distinguishes its value from fungible tokens like Bitcoin (Btc). Scammers are utilizing the open source nature of the blockchain to victimize users and steal their NFTs, leaving NFT collectors with infringed artwork. In a bid to eliminate security vulnerability and attack in NFT platform, we implemented a smart contract verification model. Our verification model is a 2-pronged approach that utilized F*, functional programming language. We presented two tools that translated solidity source code and EVM bytecode to solidity* and EVM* respectively. The EVM decompiler analyzes contracts in which the solidity source codes are unavailable as well as low level properties of contracts. The EVM* and Solidity* tools helped to check the equivalence between a solidity program and the bytecode output from the solidity compiler in order to avoid bugs and preserve verified properties at the source level. In this paper, Etherscan token tracker was used to verify and authenticate NFT token before buying or minting such NFT. Keywords: Non-Fungible Tokens (NFTs), The NFT- marketplace (NFTM), Ethereum
Aarushi Goel, Matthew Green, Mathias Hall-Andersen, Gabriel Kaptchuk
Abstract Set membership proofs are an invaluable part of privacy preserving systems. These proofs allow a prover to demonstrate knowledge of a witness w corresponding to a secret element x of a public set, such that they jointly satisfy a given NP relation, i.e. â( w, x ) = 1 and x is a member of a public set { x 1 , . . . , x đ }. This allows the identity of the prover to remain hidden, eg. ring signatures and confidential transactions in cryptocurrencies. In this work, we develop a new technique for efficiently adding logarithmic-sized set membership proofs to any MPC-in-the-head based zero-knowledge protocol (Ishai et al. [STOCâ07]). We integrate our technique into an open source implementation of the state-of-the-art, post quantum secure zero-knowledge protocol of Katz et al. [CCSâ18].We find that using our techniques to construct ring signatures results in signatures (based only on symmetric key primitives) that are between 5 and 10 times smaller than state-of-the-art techniques based on the same assumptions. We also show that our techniques can be used to efficiently construct post-quantum secure RingCT from only symmetric key primitives.
Abstract : Peopleâs lives have been profoundly impacted by the headway of innovation which has worked on their lives from each viewpoint. Clearly, innovation assumes a significant part in each circle of life and information stockpiling and sharing is a significant part of it. Current information sharing and storage devices depend on trusted third parties (TTP) and because of the contribution of third parties, such frameworks need straightforwardness, security, trust and strength. To solve these issues, this paper proposes a blockchain-based secure information sharing application by consolidating the highlights of IPFS and Ethereum. In this proposed scheme ethereum blockchain, decentralized storage, encryption and IPFS are combined to build an application that maximizes the tech<em>nological resources and provide</em> with an effective storage website ,Ethereum blockchain, decentralized capacity, encryption, and InterPlanetary File System are consolidated to assemble an application that boosts the innovative assets and gives a viable storage site. To carry out the proposed situation, smart contracts are written in solidity and sent on the nearby Ethereum test network. The proposed plot accomplishes security, transparency, legitimacy of owner, access control and nature of information.
Jusop Choi, Wonseok Choi, William Aiken, Hyoungshick Kim ¡ 8 authors
Since Bitcoin appeared in 2009, over 6,000 different cryptocurrency projects have followed. The cryptocurrency world may be the only technology where a massive number of competitors offer similar services yet claim unique benefits, including scalability, fast transactions, and security. But are these projects really offering unique features and significant enhancements over their competitors? To answer this question, we conducted a large-scale empirical analysis of code maintenance activities, originality and security across 592 crypto projects. We found that about half of these projects have not been updated for the last six months; over two years, about three-quarters of them disappeared, or were reported as scams or inactive. We also investigated whether 11 security vulnerabilities patched in Bitcoin were also patched in other projects. We found that about 80% of 510 C-language-based cryptocurrency projects have at least one unpatched vulnerability, and the mean time taken to fix the vulnerability is 237.8 days. Among those 510 altcoins, we found that at least 157 altcoins are likely to have been forked from Bitcoin, about a third of them containing only slight changes from the Bitcoin version from which they were forked. As case studies, we did a deep dive into 20 altcoins (e.g., Litecoin, FujiCoin, and Feathercoin) similar to the version of Bitcoin used for the fork. About half of them did not make any technically meaningful change - failing to comply with the promises (e.g., about using Proof of Stake) made in their whitepapers.
ASBK (named after the authors' initials) is a recent blockchain protocol tackling data availability attacks against light nodes, employing two-dimensional Reed-Solomon codes to encode the list of transactions and a random sampling phase where adversaries are forced to reveal information. In its original formulation, only codes with rate $1/4$ are considered, and a theoretical analysis requiring computationally demanding formulas is provided. This makes ASBK difficult to optimize in situations of practical interest. In this paper, we introduce a much simpler model for such a protocol, which additionally supports the use of codes with arbitrary rate. This makes blockchains implementing ASBK much easier to design and optimize. Furthermore, disposing of a clearer view of the protocol, some general features and considerations can be derived (e.g., nodes behaviour in largely participated networks). As a concrete application of our analysis, we consider relevant blockchain parameters and find network settings that minimize the amount of data downloaded by light nodes. Our results show that the protocol benefits from the use of codes defined over large finite fields, with code rates that may be even significantly different from the originally proposed ones.
Light nodes in blockchain systems are known to be vulnerable to data availability (DA) attacks where they accept an invalid block with unavailable portions. Previous works have used LDPC and 2-D Reed Solomon (2D-RS) codes with Merkle Trees to mitigate DA attacks. While these codes have demonstrated improved performance across a variety of metrics such as DA detection probability, they are difficult to apply to blockchains with large blocks due to generally intractable code guarantees for large codelengths (LDPC), large decoding complexity (2D-RS), or large coding fraud proof sizes (2D-RS). We address these issues by proposing the novel Polar Coded Merkle Tree (PCMT) which is a Merkle Tree built from the encoding graphs of polar codes and a specialized polar code construction called Sampling-Efficient Freezing (SEF). We demonstrate that the PCMT with SEF polar codes performs well in detecting DA attacks for large block sizes.
Mehrdad Kiamari, Bhaskar Krishnamachari, Muhammad Naveed, Seokgu Yun
We present Blizzard, a Byzantine fault tolerant (BFT) distributed ledger protocol that is aimed at making mobile devices first-class citizens in the consensus process. Blizzard introduces a novel two-tier architecture by having the mobile nodes communicate through online brokers, and includes a decentralized matching scheme to ensure each node connects to a certain number of random brokers. Through mathematical analysis, we derive a guaranteed safety region (i.e., the set of ratios of malicious nodes and malicious brokers for which the safety is assured) for the Blizzard protocol. Liveness is shown as well. We analyze the performance of Blizzard in terms of its throughput, latency, and message complexity. Through experiments based on a software implementation, we show that Blizzard is capable of throughput on the order of several thousand transactions per second per shard and sub-second confirmation latency.
Activation functions are critical components of neural networks, helping the model learn highly-intricate dependencies, trends, and patterns. Non-linear activation functions allow the model to behave as a functional approximator, learning complex decision boundaries and multi-dimensional patterns in the data. Activation functions can be combined with one another to learn better representations with the objective of improving gradient flow, performance metrics reducing training time and computational cost. Recent work on oscillatory activation functions\cite{noel2021growing}\cite{noel2021biologically} showcased their ability to perform competitively on image classification tasks using a compact architecture. Our work proposes the utilization of these oscillatory activation functions for predicting the volume-weighted average of Bitcoin on the G-Research Cryptocurrency Dataset. We utilize a popular LSTM architecture for this task achieving competitive results when compared to popular activation functions formally used.
In equity trading, internalization is the predominant execution method for uninformed order flow, allowing retail brokers to realize cost savings and thereby offer price improvements to customers. In cryptocurrency trading, there are doubts as to whether informed and uninformed traders can be distinguished in the same way, leading brokers to seek cost savings through internal order matching instead. Using the historical order flow of the German cryptocurrency broker BISON, we present a prediction-based approach to internal order matching: Upon receiving a customer order, our model forecasts whether future order flow will be sufficient to neutralize the order before the settlement date. With a prediction accuracy of 85%, it enables brokers to match three-quarters of order volume internally, which is three times as much as a traditional static approach, and realize meaningful cost savings, even after accounting for common minimum price improvements.
The main aim of the paper is to contribute to the discussion of cryptocurrency pricing through asset pricing models. The paper develops multifactor models for the cryptocurrency valuation and discusses the elements of these models based on the literature review of scholarly articles, books, and scientific databases. We further developed the models from unit factor to five factors in order to observe whether the development is achieved by adding new factors into the model. Consequently, we pointed out the most influential factor that determines the value of cryptocurrencies.
Digital currency, which is a kind of digital token that exists on a distributed and decentralized ledger, is under the spotlight of the public's discussion. Chinese government desires to promote the establishment of a currency service system that is oriented to the digital economy era, which is beneficial to the public, and universally innovative and open. This essay introduces the reasons that the Chinese government aims to promote a new type of digital RMB, and the disadvantages the digital currency is facing now such as regulatory problems compared with existing third-party payment methods and the impact of the promotion of digital currency on third-party payment. To solve these problems, this study focuses on the integration of third-party payment and digital currency, the traffic of third-party payment and digital currency users, and the security of the blockchains. This study aims to solve the practical problems which the digital currency might face and help to promote the development of digital RMB.
This paper uses CSSD developed by Two sets of cryptocurrencies were considered, one containing the 34 largest cryptocurrencies by market capitalisation and the other containing 15 cryptocurrencies with market capitalisations under $200 million. Any cryptocurrencies launched after 21/09/2018 were excluded from the samples in the interests of consistency. Using CSSD, no herding was detected while with CSAD a weak herding effect was observed, though the results were not statistically significant. This paper has important implications for cryptocurrency investors, researchers, and policymakers.
In this article, we discuss a valuation framework for Decentralized Autonomous Organizations (DAOs). As previous work on DAO valuation is limited, we attempt to introduce a formalized framework on the subject. Although we base ourselves on conceptual frameworks from corporate finance, we introduce DAO-native valuation concepts. We argue that DAO token valuation can be mainly done in two ways, namely, according to a fundamental valuation approach and a comparable analysis approach. In the fundamental valuation approach we attempt to value the DAO token according to fundamentals while in the comparables approach we attempt to compare DAO tokens based on various metrics. Finally, we discuss various token specific considerations to potentially take into account in the valuation exercise. A valuation framework would allow the community to gauge DAOsâ performance in value generation for token stakeholders and help introduce more accountability towards the development teams behind the DAO.
Although distributed ledger technology (DLT) provides new and distinct benefits for information systems, some of its features, such as slower data processing, are incompatible with many applications. A new DLT architecture based on main-sub-ledger is presented in this paper. It achieves physical data isolation, ensuring the privacy and security of business data. Simultaneously, the main-sub-ledger creates tiered data storage, effectively relieving node data storage pressure and improving data processing capacity.