Blockchain Papers

Qiang Qu, Ildar Nurgaliev, Muhammad Muzammal, Christian S. Jensen · 5 authors

No abstract is available for this record.

Dennis Przytarski

\n Current permissioned blockchain systems utilize the key-value data\n model to store and query the ledger. As the key-value pairs are not\n sufficiently expressive to represent relationships between data, we\n present a proposal for the utilization of triples as the data model\n for blockchain systems. This approach enables a powerful query\n engine and reduces the number of data stores that have to be\n maintained.\n

Danning Sui, Gëzim Sejdiu, Damien Graux, Jens Lehmann

With the recent trend on blockchain, many users want to know more about the important players of the chain. In this study, we investigate and analyze the Ethereum blockchain network in order to identify the major entities across the transaction network. By leveraging the rich data available through Alethio's platform in the form of RDF triples we learn about the Hubs and Authorities of the Ethereum transaction network. Alethio uses SANSA for effcient reading and processing of such large-scale RDF data (transactions on Ethereum blockchain) in order to perform analytics e.g. finding top accounts, or typical behavior patterns of exchanges' deposit wallets and more.

Abdelkader Hameurlain, Roland Wagner

No abstract is available for this record.

Jongbeen Han, Heemin Kim, Hyeonsang Eom, Jonathan Coignard · 6 authors

A blockchain is designed to make consistent and reliable agreement in an unreliable and decentralized environment. It also permits processing transactions, making smart contracts, which allows end users to perform the contracts without any intermediate entities. However, there are some challenges in retrieving the state in a smart contract on the blockchain. For example, an external database or user-defined data structures can be used to retrieve the data from a smart contract in a range, which can increase the management overhead and decrease the overall performance of the blockchain system. In this paper, we propose a scheme that enables SQL query operations in a blockchain system. In our proposed scheme, the register and query managers provide fast retrieval of range data without any user-defined data structure, and management at low cost without any external database, respectively. We have implemented our scheme on quorum which is an Ethereum-based blockchain system and evaluated it using a synthetic benchmark. The experimental results show that our system can improve the search performance up to about 22x compared with the existing system with low memory usage.

Linxiang Cai, Binjun Wang

Aiming at the problem of illegal activities of Bitcoin, in this paper, transaction data structure of Bitcoin and data storage mechanism of Bitcoin Core (official client for Bitcoin) and are firstly analyzed, then a MapReduce-based structured method for processing transaction data from Bitcoin Core is introduced. Based on above knowledge, mechanisms of tracking and tracing Bitcoin fund flows are proposed, along with the visualization powered by D3.js. This paper provides a practical tool for researching and analyzing flows of illegal transaction funds.

Mohammed Almukaynizi, Vivin Paliath, Malay Shah, Malav Shah · 5 authors

With the recent prevalence of darkweb/deepweb (D2web) sites specializing in the trade of exploit kits and malware, malicious actors have easy-access to a wide-range of tools that can empower their offensive capability. In this study, we apply concepts from causal reasoning, itemset mining, and logic programming on historical cryptocurrency-related cyber incidents with intelligence collected from over 400 D2web hacker forums. Our goal was to find indicators of cyber threats targeting cryptocurrency traders and exchange platforms from hacker activity. Our approach found interesting activities that, when observed together in the D2web, subsequent cryptocurrency-related incidents are at least twice as likely to occur than they would if no activity was observed. We also present an algorithmic extension to a previously-introduced algorithm called APT-Extract that allows to model new semantic structures that are specific to our application.

Mariia Sigova, Igor Klioutchnikov, Anna Zatevakhina, Oleg I. Klioutchnikov

Is the distributed ledger technology able to predict the capital asset prices and digitizes any financial market participant? Prediction is a scary and tempting place to venture, profitable trading and the development of effective strategies. Will predictions fit into the everyday practice of financial markets? Is blockchain technology capable to revolutionize predictions? Is the blockchain able to compensate of the lack of individual intelligence in assessing market prospects? In the article, the authors do not so much raise these questions as they try to outline the directions for their solution. Financial inclusion is one of the problems that blockchain technology can solve, if it is applied properly. Transferring predictions to the online mode and providing each market participant with the opportunity to digitize their activities would help introduce new efficient mechanisms to improve performance of financial market practices. The article discusses two aspects of using blockchain technology in finance - forecasting financial markets using “collective knowledge” and digitizing assets of market participants based on blockchain. The article also raises the question of the possibility of using some fundamental physical laws for analyzing the impact of new technologies on the financial markets. An attempt is made to approach the assessment of the prospects of using a number of decentralized applications for financial market predictions and the creation of digital counterparts of market participants. A fundamental lesson from experiments in predicting financial markets and digitizing market participants is that decentralized solutions are still not sufficiently scaled and, as a result, are used by consumers.

B. Moustapha

In this paper, we revisit the fundamental question of Bitcoins security against selfish-mine attack introduced by I. Eyal and E. G. Sirer in We study the state machine of Bitcoin's network under the influence of one pool miner adopting the selfish mine strategy while the rest of the community following the standard protocol. We prove that the process following by the states of Bitcoin's system is a irreducible, positive-recurrent, aperiodic, and discrete Markov chain. We give an invariant (stationary) distribution for this Markov chain and deduce easily the rate of convergence towards the stationary equilibrium situation.

Ildar Nurgaliev, Muhammad Muzammal, Qiang Qu

No abstract is available for this record.

Ben Berger, Zvika Brakerski

We consider natural ways to extend the notion of Zero-Knowledge (ZK) Proofs beyond decision problems. Specifically, we consider search problems, and define zero-knowledge proofs in this context as interactive protocols in which the prover can establish the correctness of a solution to a given instance without the verifier learning anything beyond the intended solution, even if it deviates from the protocol. The goal of this work is to initiate a study of Search Zero-Knowledge (search-ZK), the class of search problems for which such systems exist. This class trivially contains search problems where the validity of a solution can be efficiently verified (using a single message proof containing only the solution). A slightly less obvious, but still straightforward, way to obtain zero-knowledge proofs for search problems is to let the prover send a solution and prove in zero-knowledge that the instance-solution pair is valid. However, there may be other ways to obtain such zero-knowledge proofs, and they may be more advantageous. In fact, we prove that there are search problems for which the aforementioned approach fails, but still search zero-knowledge protocols exist. On the other hand, we show sufficient conditions for search problems under which some form of zero-knowledge can be obtained using the straightforward way.

Elvira Albert, Pablo Gordillo, Benjamin Livshits, Albert Rubio · 5 authors

Analyzing Ethereum bytecode, rather than the source code from which it was generated, is a necessity when: (1) the source code is not available (e.g., the blockchain only stores the bytecode), (2) the information to be gathered in the analysis is only visible at the level of bytecode (e.g., gas consumption is specified at the level of EVM instructions), (3) the analysis results may be affected by optimizations performed by the compiler (thus the analysis should be done ideally after compilation). This paper presents EthIR, a framework for analyzing Ethereum bytecode, which relies on (an extension of) OYENTE, a tool that generates CFGs; EthIR produces from the CFGs, a rule-based representation (RBR) of the bytecode that enables the application of (existing) high-level analyses to infer properties of EVM code.

Carlos Pérez-Leguízamo, Juan Sebastian Guadalupe Godinez-Borja

Services Oriented Architectures (SOA) represents a new model in the traditional way of designing systems because it is constructed around individual processes of different areas in an organization. In recent years, the necessity to integrate critical applications in a SOA has increased, that is the case of the Financial Applications. These applications require high reliability, information consistency and timeliness that are not satisfied by conventional SOA infrastructures. In this article we present a novel approach of combining SOA with Autonomous Decentralized Systems (ADS) in order to provide an infrastructure that can satisfy those requirements. We have named this infrastructure Autonomous Decentralized Service Oriented Architecture (ADSOA). We present the concept and architecture of ADSOA, as well as the basic technologies for its realization. Moreover, a real implementation in a mission critical banking transaction processing system is shown in order to prove its effectiveness.

Allan Third, John Domingue

Searching for information in distributed ledgers is currently not an easy task, as information relating to an entity may be scattered throughout the ledger with no index. As distributed ledger technologies become more established, they will increasingly be used to represent real world transactions involving many parties and the search requirements will grow. An index providing the ability to search using domain specific terms across multiple ledgers will greatly enhance to power, usability and scope of these systems.

Eli Ben‐Sasson, Alessandro Chiesa, Michael A. Forbes, Ariel Gabizon · 6 authors

We study the problem of constructing proof systems that achieve both soundness and zero knowledge unconditionally (without relying on intractability assumptions). Known techniques for this goal are primarily combinatorial, despite the fact that constructions of interactive proofs (IPs) and probabilistically checkable proofs (PCPs) heavily rely on algebraic techniques to achieve their properties.

Bernhard Haslhofer, Roman Karl, Erwin Filtz

Bitcoin is a rising digital currency and exemplifies the grow- ing need for systematically gathering and analyzing pub- lic transaction data sets such as the blockchain. However, the blockchain in its raw form is just a large ledger listing transfers of currency units between alphanumeric character strings, without revealing contextually relevant real-world information. In this demo, we present GraphSense, which is a solution that applies a graph-centric perspective on digital currency transactions. It allows users to explore transactions and follow the money ow, facilitates analytics by semantically enriching the transaction graph, supports path and graph pattern search, and guides analysts to anomalous data points. To deal with the growing volume and velocity of transaction data, we implemented our solution on a horizontally scalable data processing and analytics infrastructure. Given the ongoing digital transformation in financial services and technologies, we believe that our approach contributes to development of analytics solutions for digital currency ecosystems, which is relevant in fields such as financial analytics, law enforcement, or scientific research

Iddo Bentov, Rafael Pass, Elaine Shi

No abstract is available for this record.

Rodrigue Carlos Nana Mbinkeu, Bernabé Batchakui

For the past five years, the bitcoin network constantly experience a growth in its size as more communities turn to accept the currency for payment exchanges. Using Flat File and a LevelDB of indices to save blocks on disk, bitcoin users require more memory to save the history of transaction. We focus on issues of memory management and access time in the bitcoin protocol using SQLite DataBase. With all the advantages of SQLite DataBase, it would be efficient if it is fitted in this architecture. The SQLite comes with many flavors one of which is its ability to support sql queries. Thus, instead of parsing indices to search a block from the database, a more powerful query can do the job.

Federica Mandreoli, Riccardo Martoglia, Wilma Penzo, Simona Sassatelli · 5 authors

No abstract is available for this record.

Oded Goldreich

Various types of probabilistic proof systems have played a central role in the development of computer science in the last couple of decades. These proof systems deviate from the traditional concept of a proof by introducing randomization and interaction into the verification process. Probabilistic proof systems carry an error probability (which is explicitly bounded and can be decreased by repetitions), but they offer various advantages over deterministic proof systems. This primer concentrates on three types of probabilistic proof systems: interactive proofs, zero-knowledge proofs, and Probabilistically Checkable Proofs (PCP). Surveying the basic results regarding these proof systems, we stress the essential role of randomness in each of them.

ICSOC 2020 Online, Kafeza, Eleanna, Benatallah, Boualem, Martinelli, Fabio · 7 authors

No abstract is available for this record.

Cudré-Mauroux, Philippe

In the past, the problem of semantic interoperability in information systems was mostly solved by means of centralization, both at a system and at a logical level. This approach has been successful to a certain extent, but offers limited scalability and flexibility. Peer-to-Peer systems as a new brand of system architectures indicate that the principles of decentralization and self-organization might offer new solutions to many problems that scale well to very large numbers of users, or to systems where central authorities do not prevail. Therefore, we suggest a new way of building global agreements, i.e., semantic interoperability, based on decentralized, self-organizing interactions only. In the first part of this thesis, we discuss traditional data integration techniques relying on global schemas, perfect schema mappings and contained query rewritings. We elaborate on the current ecology of the World Wide Web, where autonomous information sources come and go in dynamic and unpredictable ways. In the current environment, data, schemas and schema mappings can all be generated without human intervention and get encoded in syntactic structures with limited expressivity. We argue that traditional top-down integration techniques are inapplicable to that new context and propose a new integration architecture based on decentralized mappings and dynamic self-organization. In the second part of this thesis, we propose a set of principles to foster semantic interoperability in very large scale information systems. We start by introducing new metrics for the schema mappings, based on both syntactic losses (completeness) and semantic mismatch (soundness) to selectively reformulate queries in a decentralized network of heterogeneous parties. We detail analytical methods to evaluate our metrics, and show how to take advantage of those methods to gradually alleviate mapping inconsistencies across the network. We describe a totally decentralized message passing scheme using belief propagation on transitive closures of schema mapping operations to efficiently evaluate the degree of semantic mismatch between pairs of acquainted information systems. Finally, we propose a graph-theoretic analysis of the network of mappings to quantify the quality of the global agreement that can be achieved in that way. The third and last part of this thesis is devoted to the presentation of two systems illustrating the practical applicability of our ideas. The first system we introduce, GridVine, is a Semantic Overlay Network supporting decentralized data integration techniques through pairwise schema mappings and monotonic schema inheritance. GridVine follows the principle of data independence by separating a logical layer, the semantic overlay for managing and mapping data and schemas, from a physical layer consisting of a self-organizing Peer-to-Peer overlay network for efficient routing of messages. The second system, called PicShark, takes advantage of semi-structured metadata to meaningfully share pictures in collaborative settings. PicShark builds on our principles to dynamically create both annotations and mappings, and to gradually minimize information entropy – in terms of missing metadata and schematic heterogeneity – in a self-organizing and decentralized context. Throughout this thesis, we advocate a holistic view on semantics in large-scale information systems: we model semantics as bottom-up and dynamic agreements among heterogeneous parties. We consider both the representation of semantics and the discovery of the interpretation of symbols as the result of a self-organizing process performed by distributed agents whose utility functions depend on the proper interpretation of the symbols. Our view sharply contrasts with previous top-down contributions analyzing data sources in isolation or focusing on global vocabularies and rigid sets of interpretations curated off-line. In a world where digital information is abundant but human attention remains scarce, we believe that autonomous, best-effort processes such as the ones proposed throughout this thesis will play an ever increasing role in complementing traditional top-down integration approaches to handle massive amounts of digitalized and heterogeneous information assets.

Narendra Kunapareddy, Parsa Mirhaji, David Richards, S. Ward Casscells

Although the decentralized and autonomous implementation of health information systems has made it possible to extend the reach of surveillance systems to a variety of contextually disparate domains, public health use of data from these systems is not primarily anticipated. The Semantic Web has been proposed to address both representational and semantic heterogeneity in distributed and collaborative environments. We introduce a semantic approach for the integration of health data using the Resource Definition Framework (RDF) and the Simple Knowledge Organization System (SKOS) developed by the Semantic Web community.

Anqing Zhu

Digital signature is used to assure the data integrity,confidentiality and non-repudiation of the document being transmitted over the network.The combination of XML and digital signature is superior to traditional digital signature.This paper discusses a scheme of XML digital signature.This scheme is based on zero-knowledge proof,and is implemented by Java.It describes how to sign and verify a XML document with the digital signature scheme.