Bitcoin is an application that runs on blockchain technology. Blockchain is a foundational technology that is bringing in the second era of the Internet – the era where value can be transferred, rather than just information.
Blockchain is developing along a four-stage path similar to that which TCP/IP took. Both are foundational technologies. TCP/IP brought the Internet, and eventually brought significant (transformational) technological changes in business like Amazon.com and Skype. These are changes that could not have been forecast at the beginning of the Internet age.
Blockchain is an immutable distributed ledger. It replaces the inefficient use of multiple centralized ledgers. It will support smart contracts that automatically make payments, adjust accounts, and coordinate records among multiple organizations.
A payroll application on blockchain’s distributed ledger will allow employees to be paid, and all related deductions and deposits to be made in real-time. It will allow multiple government agencies to immediately have audit-level access to all employee records, and all employer matching-payments. With a fiat crypto-currency a payroll application on the blockchain will allow immediate global payroll compliance at a fraction of the cost of current payroll compliance.
Based on the trajectory of ITP/IP’s development it is reasonable to assume that a payroll application will be seen on a blockchain (most likely Quorum, a private/permissioned blockchain based on the Ethereum platform) by 2018-2021. The first one will be constructed either by a government (Finland or Estonia) or by a private company (in the USA). Costs will be so low that the industry will consolidate (picture the arrival of Amazon.com among the group of brick and mortar books stores that preceded it in the late 1990’s).
A traditional payroll service provider today needs to prepare for this change by developing a pilot program internally that will educate its workforce to the advantages and operational intricacies of a service based in the blockchain.
The Bitcoin digital currency appeared in 2009. Since this time, researchers and practitioners have looked under the hood of the open source Bitcoin currency, and discovered that Bitcoins Blockchain software architecture is useful for non-monetary purposes too. By coalescing the research and practice on Blockchains, this work begins to unpack Blockchains as a general phenomenon, therein, arguing that all Blockchain phenomena can be conceived as being comprised of transaction platforms and digital ledgers, and illustrating where public key encryption plays a differential role in facilitating these features of Blockchains.
Heretofore the concept of "blockchain" has not been precisely defined. Accordingly the potential useful applications of this technology have been largely inflated. This work sidesteps the question of what constitutes a blockchain as such and focuses on the architectural components of the Bitcoin cryptocurrency, insofar as possible, in isolation. We consider common problems inherent in the design of effective supply chain management systems. With each identified problem we propose a solution that utilizes one or more component aspects of Bitcoin. This culminates in five design principles for increased efficiency in supply chain management systems through the application of incentive mechanisms and data structures native to the Bitcoin cryptocurrency protocol.
Emanuele Di Pascale, Jasmina McMenamy, Irene Macaluso, Linda Doyle
The disruptive power of blockchain technologies represents a great opportunity to re-imagine standard practices of telecommunication networks and to identify critical areas that can benefit from brand new approaches. As a starting point for this debate, we look at the current limits of infrastructure sharing, and specifically at the Small-Cell-as-a-Service trend, asking ourselves how we could push it to its natural extreme: a scenario in which any individual home or business user can become a service provider for mobile network operators, freed from all the scalability and legal constraints that are inherent to the current modus operandi. We propose the adoption of smart contracts to implement simple but effective Service Level Agreements (SLAs) between small cell providers and mobile operators, and present an example contract template based on the Ethereum blockchain.
One of the fundamental applications for a practically useful system of money is remuneration. Information pertaining to the amount of compensation awarded to different individuals is often considered sensitive, commanding a certain degree of privacy. As Bitcoin and similarly designed cryptocurrencies evolve into a recognized medium of exchange for larger swaths of the world economy, an increasing number of people will earn income in the form of blockchain-based payments. The nature of these transactions is such that the minute details of an affected individuals compensation package and spending habits will be exposed to public scrutiny. In some cases this violates cultural norms which respect the confidentiality of salaries, yet in other cases it could be regarded as providing the benefits associated with greater transparency. In this work we analyse the Bitcoin blockchain record of periodic payments accruing to an individual address in exchange for goods or services rendered. For differing levels of available information we seek to determine the extent of insights that can be gleaned about the transacting counter-parties and the privacy implications this entails.
Tien Tuan Anh Dinh, Ji Wang, Gang Chen, Rui Liu · 6 authors
Blockchain technologies are taking the world by storm. Public blockchains, such as Bitcoin and Ethereum, enable secure peer-to-peer applications like crypto-currency or smart contracts. Their security and performance are well studied. This paper concerns recent private blockchain systems designed with stronger security (trust) assumption and performance requirement. These systems target and aim to disrupt applications which have so far been implemented on top of database systems, for example banking, finance applications. Multiple platforms for private blockchains are being actively developed and fine tuned. However, there is a clear lack of a systematic framework with which different systems can be analyzed and compared against each other. Such a framework can be used to assess blockchains' viability as another distributed data processing platform, while helping developers to identify bottlenecks and accordingly improve their platforms. In this paper, we first describe BlockBench, the first evaluation framework for analyzing private blockchains. It serves as a fair means of comparison for different platforms and enables deeper understanding of different system design choices. Any private blockchain can be integrated to BlockBench via simple APIs and benchmarked against workloads that are based on real and synthetic smart contracts. BlockBench measures overall and component-wise performance in terms of throughput, latency, scalability and fault-tolerance. Next, we use BlockBench to conduct comprehensive evaluation of three major private blockchains: Ethereum, Parity and Hyperledger Fabric. The results demonstrate that these systems are still far from displacing current database systems in traditional data processing workloads. Furthermore, there are gaps in performance among the three systems which are attributed to the design choices at different layers of the software stack.
Ponzi schemes are financial frauds which lure users under the promise of high profits. Actually, users are repaid only with the investments of new users joining the scheme: consequently, a Ponzi scheme implodes soon after users stop joining it. Originated in the offline world 150 years ago, Ponzi schemes have since then migrated to the digital world, approaching first the Web, and more recently hanging over cryptocurrencies like Bitcoin. Smart contract platforms like Ethereum have provided a new opportunity for scammers, who have now the possibility of creating "trustworthy" frauds that still make users lose money, but at least are guaranteed to execute "correctly". We present a comprehensive survey of Ponzi schemes on Ethereum, analysing their behaviour and their impact from various viewpoints.
Bitcoin is attracting a steadily increasing interest since its first appearance in 2008. Bitcoin price forecasting would be of great practical interest given its role as a relatively new virtual “currency”. This presupposes the modeling and verification of some kind of relation, causal or not, connecting bitcoin price to other “established” factors of economic interest. Towards this goal, cross-correlation analysis is used in this work to investigate relations between bitcoin price and a set of other factors of economic interest. The years 2013 to 2015 are selected as the temporal basis of this research, because earlier bitcoin prices were practically zero. Results reveal a strong correlation between bitcoin and stock market indices or other economical factor values. SWOT analysis for bitcoin is carried out for the same period of time, based on cross-correlation as well as on existing research results. Bitcoin is seen to possess more benefits than risks, while its strong temporal correlations with other economic indices or prices constitute an opportunity to be further explored towards the goal of bitcoin price forecasting.
Fintech is a term given to financial technology in the digital age. At its core sit the twin concepts of blockchain and distributed ledgers. These technology solutions bring with them the promise of faster, cheaper, more secure and transparent financial transactions over the internet. In a more widely used context, Fintech is conceived and even defined as enabling disruptive innovation in financial markets and financial services. This briefing explains what Fintech is and investigates whether the promise of Fintech is hype or reality. It also highlights the resultant policy implications that are generated by the phenomena and what issues lawmakers should be cognisant of.
We introduce blockchains and distributed ledgers and describe their potential applications to money and banking. The analysis compares public and private ledgers and outlines the suitability of various types of ledgers for different purposes. Furthermore, a few historical prototypes of blockchains and distributed ledgers are presented, and results of their hard forking are illustrated. Next, some potential applications of distributed ledgers to trading, clearing and settlement, payments, trade finance, etc. are outlined. Monetary circuits are argued to be natural applications for blockchains. Finally, the role of digital currencies in modern society is articulated and various forms of digital cash, such as central bank issued electronic cash, bank money, bitcoin and P2P money, are compared and contrasted. Keywords: blockchains, distributed ledgers, digital currencies, modern monetary circuit; credit creation banking; interconnected banking network.
In zunehmendem Maße wird das Finanzsystem von digitalen Technologien beeinflusst. Welche Potenziale bringen diese neuen Technologien für das Geld- und Austauschsystem mit sich? Und wie können diese für eine nachhaltige Entwicklung eingesetzt werden?
We present the concept of leveraging Blockchain technology, for the management and security of information related to the Internet Of Things. Here, we put forth a model for the intercommunication of smart devices, their identity management and information security, with Blockchain posing as the backbone. The model proposes to serve as a robust and scalable solution, in order to address the security and identity concerns, arising due to the distributed nature of the Internet of Things. The proposed model is further compared to the existing ones in practice.
A ledgerLedger can be defined as a “book of permanent record.” With modern information technology, data have become economic resources if they are associated with exclusive owners and put into a ledgerLedger. It is shown in Chaps. 3 and 4 that IoTInternet of Things (IoT) data can be transformed into productive resources while Chaps. 5 and 6 show that transaction data can be turned into money-likeMoney bank deposit currenciesDeposit currency.
During times of extreme market turmoil, it is acknowledged that there is a tendency towards "flight to safety". A strong (weak) safe haven is defined as an asset that has a significant positive (negative) return in periods where another asset is in distress, while hedge has to be negatively correlated (uncorrelated) on average. The Bitcoin's surge alongside the aftermath of Trump's win in the 2016 U.S. presidential elections has strengthened its status as the modern safe haven. This paper uses a truly noise-assisted data analysis method, termed as Ensemble Empirical Mode Decomposition-based approach, to examine whether Bitcoin can act as a hedge and safe haven for U.S. stock price index. The results document that the Bitcoin's safe-haven property is time-varying and that it has primarily been a weak safe haven in the short term and the long-term. We also demonstrate that precious metals lost their safe haven properties over time as the correlation between gold/silver and U.S. stock price declines from short-to long-run horizons.
Steve Huckle, Martin White, Rituparna Bhattacharya
In this paper, we discuss an application that uses blockchain technology to transfer fiat money into a cryptocurrency — Ether. A typical use of this technology could be to become a component of a larger system, whereby, after traveling, a customer can exchange leftover foreign currency for their local denomination. However, a more interesting application could be to convert fiat money into a cryptocurrency to facilitate a demonetisation scheme, such as that implemented recently in India. In the latter context, we describe the development of our blockchain application against the ramifications of demonetisation and whether the Indian government could have augmented that scheme through technology such as ours. We discuss why the Indian government has not contemplated such a measure, which also leads to a discussion of whether they might have considered adopting their own cryptocurrency. However, even though the Indian public seems willing to adopt the technology, we find that unlikely. Finally, we show that our application demonstrates that fiat money to cryptocurrency conversion is technically feasible, but the Indian government is unlikely to consider such technology due to issues surrounding monetary sovereignty.
Andrew Miller, Iddo Bentov, Surya Bakshi, Ranjit Kumaresan · 5 authors
Bitcoin, Ethereum and other blockchain-based cryptocurrencies, as deployed today, cannot scale for wide-spread use. A leading approach for cryptocurrency scaling is a smart contract mechanism called a payment channel which enables two mutually distrustful parties to transact efficiently (and only requires a single transaction in the blockchain to set-up). Payment channels can be linked together to form a payment network, such that payments between any two parties can (usually) be routed through the network along a path that connects them. Crucially, both parties can transact without trusting hops along the route. In this paper, we propose a novel variant of payment channels, called Sprites, that reduces the worst-case "collateral cost" that each hop along the route may incur. The benefits of Sprites are two-fold. 1) In Lightning Network, a payment across a path of $\ell$ channels requires locking up collateral for $Θ(\ellΔ)$ time, where $Δ$ is the time to commit an on-chain transaction. Sprites reduces this cost to $O(\ell + Δ)$. 2) Unlike prior work, Sprites supports partial withdrawals and deposits, during which the channel can continue to operate without interruption. In evaluating Sprites we make several additional contributions. First, our simulation-based security model is the first formalism to model timing guarantees in payment channels. Our construction is also modular, making use of a generic abstraction from folklore, called the "state channel," which we are the first to formalize. We also provide a simulation framework for payment network protocols, which we use to confirm that the Sprites construction mitigates against throughput-reducing attacks.
Andrew Miller, Iddo Bentov, Ranjit Kumaresan, Christopher Cordi · 5 authors
Bitcoin, Ethereum and other blockchain-based cryptocurrencies, as deployed\ntoday, cannot scale for wide-spread use. A leading approach for cryptocurrency\nscaling is a smart contract mechanism called a payment channel which enables\ntwo mutually distrustful parties to transact efficiently (and only requires a\nsingle transaction in the blockchain to set-up). Payment channels can be linked\ntogether to form a payment network, such that payments between any two parties\ncan (usually) be routed through the network along a path that connects them.\nCrucially, both parties can transact without trusting hops along the route.\n In this paper, we propose a novel variant of payment channels, called\nSprites, that reduces the worst-case "collateral cost" that each hop along the\nroute may incur. The benefits of Sprites are two-fold. 1) In Lightning Network,\na payment across a path of $\\ell$ channels requires locking up collateral for\n$\\Theta(\\ell\\Delta)$ time, where $\\Delta$ is the time to commit an on-chain\ntransaction. Sprites reduces this cost to $O(\\ell + \\Delta)$. 2) Unlike prior\nwork, Sprites supports partial withdrawals and deposits, during which the\nchannel can continue to operate without interruption.\n In evaluating Sprites we make several additional contributions. First, our\nsimulation-based security model is the first formalism to model timing\nguarantees in payment channels. Our construction is also modular, making use of\na generic abstraction from folklore, called the "state channel," which we are\nthe first to formalize. We also provide a simulation framework for payment\nnetwork protocols, which we use to confirm that the Sprites construction\nmitigates against throughput-reducing attacks.\n
This paper critiques blockchain-based “smart contracts,” which aim to automatically and securely execute obligations without reliance on a centralized enforcement authority. Though smart contracts do have some features that might serve the goals of social justice and fairness, I suggest that they are based on a thin conception of what law does, and how it does it. Smart contracts focus on the technical form of contract to the exclusion of the social contexts within which contracts operate, and the complex ways in which people use them. In the real world, contractual obligations are enforced through all kinds of social mechanisms other than formal adjudication—and contracts serve many functions that are not explicitly legal in nature, or even designed to be formally enforced. I describe three categories of contracting practices in which people engage (the inclusion of facially unenforceable terms, the inclusion of purposefully underspecified terms, and willful nonenforcement of enforceable terms) to illustrate how contracts actually “work.” The technology of smart contracts neglects the fact that people use contracts as social resources to manage their relations. The inflexibility that they introduce, by design, might short-circuit a number of social uses to which law is routinely put. Therefore, I suggest that attention to the social and relational contexts of contracting are essential considerations for the discussion, development, and deployment of smart contracts.
Thomas Dickerson, Paul Gazzillo, Maurice Herlihy, Eric Koskinen
Modern cryptocurrency systems, such as Ethereum, permit complex financial transactions through scripts called smart contracts. These smart contracts are executed many, many times, always without real concurrency. First, all smart contracts are serially executed by miners before appending them to the blockchain. Later, those contracts are serially re-executed by validators to verify that the smart contracts were executed correctly by miners. Serial execution limits system throughput and fails to exploit today's concurrent multicore and cluster architectures. Nevertheless, serial execution appears to be required: contracts share state, and contract programming languages have a serial semantics. This paper presents a novel way to permit miners and validators to execute smart contracts in parallel, based on techniques adapted from software transactional memory. Miners execute smart contracts speculatively in parallel, allowing non-conflicting contracts to proceed concurrently, and "discovering" a serializable concurrent schedule for a block's transactions, This schedule is captured and encoded as a deterministic fork-join program used by validators to re-execute the miner's parallel schedule deterministically but concurrently. Smart contract benchmarks run on a JVM with ScalaSTM show that a speedup of of 1.33x can be obtained for miners and 1.69x for validators with just three concurrent threads.
Tyler Crain, Vincent Gramoli, Mikel Larrea, Michel Raynal
This paper presents a new Byzantine consensus algorithm targeting consortium blockchains. To this end, it first revisits the consensus validity property by requiring that the decided value satisfies a predefined predicate, which does not systematically exclude a value proposed only by Byzantine processes, thereby generalizing the validity properties found in the literature. Then, the paper presents a simple and modular Byzantine consensus algorithm that relies neither on a leader, nor on signatures, nor on randomization. It features the fastest multivalued reduction to binary consensus we know of and a time optimal binary Byzantine consensus algorithm. The multivalued reduction runs multiple instances of binary consensus concurrently, which result in a bitmask that is then applied to a vector of multivalued proposals to filter out a valid proposed value that is decided. To ensure eventual decision deterministically, the underlying binary consensus algorithm assumes eventual synchrony.
Tyler Crain, Vincent Gramoli, Mikel Larrea, Michel Raynal
This paper introduces a deterministic Byzantine consensus algorithm that relies on a new weak coordinator. As opposed to previous algorithms that cannot terminate in the presence of a faulty or slow coordinator, our algorithm can terminate even when its coordinator is faulty, hence the name weak coordinator. The key idea is to allow processes to complete asynchronous rounds as soon as they receive a threshold of messages, instead of having to wait for a message from a coordinator that may be slow. The resulting algorithm assumes partial synchrony, is resilience optimal, time optimal and does not need signatures. Our presentation is didactic: we first present a simple safe binary Byzantine consensus algorithm, modify it to ensure termination, and finally present an optimized reduction from multivalue consensus to binary consensus that may terminate in 4 message delays. To evaluate our algorithm, we deployed it on 100 machines distributed in 5 datacenters across different continents and compared its performance against the randomized solution from Mostefaoui, Moumem and Raynal [PODC14] that terminates in O(1) rounds in expectation. Our algorithm always outperforms the latter even in the presence of Byzantine behaviors. Our algorithm has a subsecond average latency in most of our geo-distributed experiments, even when attacked by a well-engineered coalition of Byzantine processes.
We correct the double spend race analysis given in Nakamoto’s foundational Bitcoin article and find the exact closed-form formula for the probability of success of a double spend attack using the regularized incomplete beta function. We give the first proof of its exponential decay on the number of confirmations, often cited in the literature, and find an asymptotic formula. Larger number of confirmations are required compared to those given by Nakamoto. We also compute this probability conditional to the knowledge of the time of the confirmations. This provides a finer risk analysis than the classical one.
Smart contracts are full-fledged programs that run on blockchains (e.g., Ethereum, one of the most popular blockchains). In Ethereum, gas (in Ether, a cryptographic currency like Bitcoin) is the execution fee compensating the computing resources of miners for running smart contracts. However, we find that under-optimized smart contracts cost more gas than necessary, and therefore the creators or users will be overcharged. In this work, we conduct the first investigation on Solidity, the recommended compiler, and reveal that it fails to optimize gas-costly programming patterns. In particular, we identify 7 gas-costly patterns and group them to 2 categories. Then, we propose and develop GASPER, a new tool for automatically locating gas-costly patterns by analyzing smart contracts' bytecodes. The preliminary results on discovering 3 representative patterns from 4,240 real smart contracts show that 93.5%, 90.1% and 80% contracts suffer from these 3 patterns, respectively.
Bitcoin is a virtual currency that is created from computer code. It has no central bank and is not backed by any government. But it can be exchanged for goods and services or for any other currencies. They were launched in 2009 as a bit of software written under the name Satoshi Nakamoto. The present paper analyse the Indian Tax and legal considerations regarding Bit coins. It also analyse the problems and risks related with Bitcoins.