1,690 research outputs found
Blockchain: A Graph Primer
Bitcoin and its underlying technology Blockchain have become popular in
recent years. Designed to facilitate a secure distributed platform without
central authorities, Blockchain is heralded as a paradigm that will be as
powerful as Big Data, Cloud Computing and Machine learning. Blockchain
incorporates novel ideas from various fields such as public key encryption and
distributed systems. As such, a reader often comes across resources that
explain the Blockchain technology from a certain perspective only, leaving the
reader with more questions than before. We will offer a holistic view on
Blockchain. Starting with a brief history, we will give the building blocks of
Blockchain, and explain their interactions. As graph mining has become a major
part its analysis, we will elaborate on graph theoretical aspects of the
Blockchain technology. We also devote a section to the future of Blockchain and
explain how extensions like Smart Contracts and De-centralized Autonomous
Organizations will function. Without assuming any reader expertise, our aim is
to provide a concise but complete description of the Blockchain technology.Comment: 16 pages, 8 figure
BlockTag: Design and applications of a tagging system for blockchain analysis
Annotating blockchains with auxiliary data is useful for many applications.
For example, e-crime investigations of illegal Tor hidden services, such as
Silk Road, often involve linking Bitcoin addresses, from which money is sent or
received, to user accounts and related online activities. We present BlockTag,
an open-source tagging system for blockchains that facilitates such tasks. We
describe BlockTag's design and present three analyses that illustrate its
capabilities in the context of privacy research and law enforcement
Inferring the interplay of network structure and market effects in Bitcoin
A main focus in economics research is understanding the time series of prices
of goods and assets. While statistical models using only the properties of the
time series itself have been successful in many aspects, we expect to gain a
better understanding of the phenomena involved if we can model the underlying
system of interacting agents. In this article, we consider the history of
Bitcoin, a novel digital currency system, for which the complete list of
transactions is available for analysis. Using this dataset, we reconstruct the
transaction network between users and analyze changes in the structure of the
subgraph induced by the most active users. Our approach is based on the
unsupervised identification of important features of the time variation of the
network. Applying the widely used method of Principal Component Analysis to the
matrix constructed from snapshots of the network at different times, we are
able to show how structural changes in the network accompany significant
changes in the exchange price of bitcoins.Comment: project website: http://www.vo.elte.hu/bitcoi
A Flexible Network Approach to Privacy of Blockchain Transactions
For preserving privacy, blockchains can be equipped with dedicated mechanisms
to anonymize participants. However, these mechanism often take only the
abstraction layer of blockchains into account whereas observations of the
underlying network traffic can reveal the originator of a transaction request.
Previous solutions either provide topological privacy that can be broken by
attackers controlling a large number of nodes, or offer strong and
cryptographic privacy but are inefficient up to practical unusability. Further,
there is no flexible way to trade privacy against efficiency to adjust to
practical needs. We propose a novel approach that combines existing mechanisms
to have quantifiable and adjustable cryptographic privacy which is further
improved by augmented statistical measures that prevent frequent attacks with
lower resources. This approach achieves flexibility for privacy and efficency
requirements of different blockchain use cases.Comment: 6 pages, 2018 IEEE 38th International Conference on Distributed
Computing Systems (ICDCS
A Petri Nets Model for Blockchain Analysis
A Blockchain is a global shared infrastructure where cryptocurrency
transactions among addresses are recorded, validated and made publicly
available in a peer- to-peer network. To date the best known and important
cryptocurrency is the bitcoin. In this paper we focus on this cryptocurrency
and in particular on the modeling of the Bitcoin Blockchain by using the Petri
Nets formalism. The proposed model allows us to quickly collect information
about identities owning Bitcoin addresses and to recover measures and
statistics on the Bitcoin network. By exploiting algebraic formalism, we
reconstructed an Entities network associated to Blockchain transactions
gathering together Bitcoin addresses into the single entity holding permits to
manage Bitcoins held by those addresses. The model allows also to identify a
set of behaviours typical of Bitcoin owners, like that of using an address only
once, and to reconstruct chains for this behaviour together with the rate of
firing. Our model is highly flexible and can easily be adapted to include
different features of the Bitcoin crypto-currency system
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