The Bitcoin has emerged as a fascinating phenomenon in the Financial markets. Without any central authority issuing the currency, the Bitcoin has been associated with controversy ever since its popularity, accompanied by increased public interest, reached high levels. Here, we contribute to the discussion by examining the potential drivers of Bitcoin prices, ranging from fundamental sources to speculative and technical ones, and we further study the potential influence of the Chinese market. The evolution of relationships is examined in both time and frequency domains utilizing the continuous wavelets framework, so that we not only comment on the development of the interconnections in time but also distinguish between short-term and long-term connections. We find that the Bitcoin forms a unique asset possessing properties of both a standard financial asset and a speculative one.
With the vast increase in smartphones, there have been an increasing number of opportunities growing in the app industry. One in particular is the way we deal with money. There are huge overheads in the current payment systems around the world particularly in the United States, many of which include large transaction fees. Many new businesses have grown to solve these inefficiencies and create a new platform that provides a new user experience, security, and convenience among many other things. However, many of these platforms are still centralized, making them more susceptible to attacks. This thesis goes over the various methods of payments, starting from their origins and discusses their flaws and ways they are being improved. This study explains where payment platforms are going and how they line up against other platforms in terms of security and usability. We look at the origins of credit cards and why the US is lagging behind other countries in credit card security. Digital wallets like PayPal, Venmo, Square, etc. have done a remarkable job, but still have room for improvement in terms of security and usage. I try to solve these problems with the mobile application AnyCoin by bringing one platform that houses different types of digital wallets. The goal of this application was to grow a large user base and collect data off the transaction for future analysis and advertising. This study goes through an in depth analysis on the application from the iv perspective of merchants and consumers to understand what users are looking for in digital wallets. Decentralized platforms and crypto-currencies like Bitcoin have also created different ways to send money by creating a trustless system that does not depend on any central authority. I discuss what Bitcoin is and exactly how it works and the flaws in the current system. Mining is the process that puts Bitcoin into circulation and secures the network. However, as more customized hardware is released, Bitcoin will fall subject to becoming more centralized, and unfortunately become heavy regulated if it is to be used as a currency. Ethereum is a new technology that takes the concepts of Bitcoin and creates a platform for a developer to create a decentralized application. I create a few contracts that show how we can create a decentralized version of PayPal that works using other crypto- currencies. Ethereum is still in its alpha stage and has yet to
The paper focuses on Romanian experiences regarding the financial strategies used by managers from pre-university education. In Romania, local public authorities provide funds to pre-university institutions. Given the sharp economic recession and the austerity measures imposed by Romanian government, the public executives had to find solutions in collecting additional funds and in spending wisely the existing financial resources. Therefore, our paper aims at examining several practices regarding: (i) employees' wages, (ii) EU funds implementing, (iii) self-financing activities, (iv) public procurement and (v) balancing strategies for the budgets, which could improve the financial management of public institutions. This also can contribute to the increase in the efficiency of spending at micro-level within public administration.
Open access
Fiscal Policies and Political Economy
Economic Analysis and Policy
Education, Management, Technology, Human Resources
This article presents one of the new elements of virtual reality, which is the Bitcoin cryptocurrency. This thesis focuses on the condition and perspectives on development of the trading function of this instrument. The authors discuss the legal aspects of functioning of the Bitcoin, conduct a SWOT analysis of this cryptocurrency as a medium of exchange, and examin the scale of use of Bitcoin in transaction purposes. As of March 1, 2014 the trading system gradually develops and the strengths of this cryptographic currency outweigh its weaknesses, but the future of Bitcoin as a medium of exchange is difficult to determine.
Alex Biryukov, Dmitry Khovratovich, Ivan Pustogarov
Bitcoin is a digital currency which relies on a distributed set of miners to mint coins and on a peer-to-peer network to broadcast transactions. The identities of Bitcoin users are hidden behind pseudonyms (public keys) which are recommended to be changed frequently in order to increase transaction unlinkability. We present an efficient method to deanonymize Bitcoin users, which allows to link user pseudonyms to the IP addresses where the transactions are generated. Our techniques work for the most common and the most challenging scenario when users are behind NATs or firewalls of their ISPs. They allow to link transactions of a user behind a NAT and to distinguish connections and transactions of different users behind the same NAT. We also show that a natural countermeasure of using Tor or other anonymity services can be cut-off by abusing anti-DoS countermeasures of the bitcoin network. Our attacks require only a few machines and have been experimentally verified. We propose several countermeasures to mitigate these new attacks.
Open access
4 source records
Blockchain Technology Applications and Security
Internet Traffic Analysis and Secure E-voting
Advanced Steganography and Watermarking Techniques
Cryptocurrencies such as bitcoin are often seen as a threat by governmental and financial institutions worldwide. Regulation could help minimise the risks involved. The author explores some legal and self-regulatory precedents from which we can learn.
I denne utredningen ønsker vi å belyse det økonomisk innovative fenomenet bitcoin. Målet med oppgaven er å få klarhet i hva bitcoin er, og med grunnlag i dette undersøke om det er en boble. I første del av utredningen presenterer vi det tekniske som ligger bak og ser på hvordan det fungerer i det økonomiske markedet. Med bakgrunn i fremlagte teorier om valuta, råvare, betalingssystemer og svindler, analyserer vi hvilken definisjon bitcoin passer best innunder. Analysen viser oss at bitcoin ser ut til å hovedsakelig fungere som spekuleringsobjekt, men at det i fremtiden kan være som betalingssystem. Dette begrunnes i lave transaksjonskostnader, noe som muliggjør mikrotransaksjoner.\nI den andre delen av utredningen forsøker vi å besvare hovedproblemstillingen vår, hvorvidt bitcoin er en boble. Vi presenterer relevant bobleteori, herunder teorier om rasjonelle og irrasjonelle bobler. Volatilitetsberegninger viser oss at bitcoin har en daglig historisk volatilitet i tidsrommet 1.januar 2012 – 26.mars 2014 på 8,5%. Vi har videre beregnet korrelasjonen mellom bitcoin sin prisutvikling og antall søk i Google til å være 0,96. Beregningene er benyttet til å analysere bitcoin opp mot bobleteori. Analysen viser oss tendenser til at det investeres i bitcoin i håp om en prisøkning i morgen, og at prisen samsvarer med publisiteten. Dette er klare indikasjoner på at markedsprisen ikke reflekterer aktivumets fundamentale faktorer. Basert på analysen fremlegger vi også våre egne beregninger på minste fundamentale verdi til bitcoin, en verdi på $252,74.\nVåre analyser og funn sett opp mot relevant bobleteori tyder på at bitcoin er en boble. Fundamental verdi er ikke gjenspeilet i prisen, man kjøper i håp om gevinst i morgen og prisen korrelerer sterkt med publisiteten.\nØkonometrisk testing er gjennomført i SPSS, mens øvrig databehandling er gjennomført i Excel.
TWith the help of the available literature, the paper attempts to assess critically the main problems of municipal finances in India and to bring out the challenges that the municipalities face with respect to revenue generation and expenditure management. The main findings suggest that the urban local bodies in India are confronted with lack of proper decentralization of functions and finances, inadequate revenue generation, expenditure shortfalls leading to poor service delivery. It also analyses the suggestions and recommendations that have been offered in the literature to cope with these critical challenges relating to urban finance.
A hard-fork reconfiguration of the peer to peer Bitcoin network is described that substitutes tamper-evident logs and proof-of-stake consensus for proof-of-work consensus. The block creation rewards and transaction fees are reallocated to establish and staff a secure financial data network capable of handling the world's transactions with subsecond response time. The new system pays dividends to stake-offering bitcoin holders. In contrast to Satoshi Nakamoto's mesh network consisting of competing peers, this system uses an enterprise class network that is efficient, robust, and scalable, consisting of cooperating peers. The network backbone nodes host trustless nomadic agents. Thousands of distributed full nodes are paid to replicate a singleton blockchain built upon every 10 minutes by a nomadic mint agent whose actions are verified by its peers. This arrangement enables immediate acknowledgment to an issuing node that its transaction has been accepted. Less effort means that subsidized transaction costs will be lower. Network reconfiguration enables the processing of numerous microtransactions. Stake-weighted distributed consensus is achieved when necessary with less than one-half arbitrarily faulty nodes. Important invariants of the Satoshi Social Contract between core developers and users are maintained: The reward schedule, the blockchain format, the fixed number of bitcoins, and the decentralized, trustless protocol are untouched. The system remains a global distributed database, with additions to the database by consent of the majority, based on a set of transparent rules they follow.
This is the first article that studies BitCoin price formation by considering both the traditional determinants of currency price, e.g., market forces of supply and demand, and digital currencies specific factors, e.g., BitCoin attractiveness for investors and users. The conceptual framework is based on the Barro (1979) model, from which we derive testable hypotheses. Using daily data for five years (2009–2015) and applying time-series analytical mechanisms, we find that market forces and BitCoin attractiveness for investors and users have a significant impact on BitCoin price but with variation over time. Our estimates do not support previous findings that macro-financial developments are driving BitCoin price in the long run.
In this paper, we propose a novel cryptographic notion called subset membership encryption (SME), and provide a very efficient SME scheme. Given a system parameter generated by an encryptor (Alice), a decryptor (Bob) generates a randomized privacy-preserved attribute token P(G) from a set of attributes G. A message is encrypted using an attribute set A chosen by Alice and P(G) provided by Bob. It requires that A is a subset of G for Bob to decrypt the message. We propose a very efficient SME scheme, where both the size of P(G) and ciphertext are short and independent of G and A. In particular, it has three useful and practical applications to oblivious transfer as follows. 1) k-Out-of-n Oblivious Transfer (OT): SME can be naturally applied to a two-round OT, which features a great communication efficiency especially for the receiver, where the receiver only sends two group elements to the message sender. 2) Priced Oblivious Transfer (POT): Our POT protocol allows a buyer to purchase any number of items in each transaction and hide selected items, price and balance from the vendor. In comparison with previous POT protocols, our protocol is more flexible and eliminates the restriction that a buyer can only purchase one item in a transaction. Our POT scheme is very efficient since it does not require any zero-knowledge proof or homomorphic encryption. 3) Restricted Priced Oblivious Transfer (RPOT): We introduce a novel POT named RPOT where a vendor can set restrictions on items or prices in POT. For example, a seller could offer a discounted price to those buyers who have purchased some specific items previously from the same seller.
Consider the radial nonlinear wave equation $-\partial_t^2 u + Δu = u^3$, $u :\mathbb{R}_t \times \mathbb{R}_x^3 \to \mathbb{R}$, $u(t,x) = u(t,|x|)$. In this paper, we construct a Gibbs measure for this system and prove its invariance under the flow of the NLW. In particular, we are in the infinite volume setting. For the finite volume analogue, specifically on the unit ball with zero boundary values, an invariant Gibbs measure was constructed by Burq, Tvetkov, and de Suzzoni as a Borel measure on super-critical Sobolev spaces. In this paper, we advocate that the finite volume Gibbs measure be considered on a space of weighted Hölder continuous functions. The measure is supported on this space and the NLW is locally well-posed there, a counter-point to the Sobolev super-criticality noted by Burq and Tzvetkov. Furthermore, the flow of the NLW leaves this measure invariant. We use a multi-time Feynman--Kac formula to construct the infinite volume limit measure by computing the asymptotics of the fundamental solution of an appropriate parabolic PDE. We use finite speed of propagation and results from descriptive set theory to establish invariance of the infinite volume measure. To the best of our knowledge, this paper provides the first construction and proof of invariance of a Gibbs measure in infinite volume outside of the 1D case.
Open access
Advanced Mathematical Physics Problems
Nonlinear Waves and Solitons
Stability and Controllability of Differential Equations
In this paper we revisit some major orthodoxies which lie at the heart of the bitcoin crypto currency and its numerous clones. In particular we look at The Longest Chain Rule, the monetary supply policies and the exact mechanisms which implement them. We claim that these built-in properties are not as brilliant as they are sometimes claimed. A closer examination reveals that they are closer to being... engineering mistakes which other crypto currencies have copied rather blindly. More precisely we show that the capacity of current crypto currencies to resist double spending attacks is poor and most current crypto currencies are highly vulnerable. Satoshi did not implement a timestamp for bitcoin transactions and the bitcoin software does not attempt to monitor double spending events. As a result major attacks involving hundreds of millions of dollars can occur and would not even be recorded. Hundreds of millions have been invested to pay for ASIC hashing infrastructure yet insufficient attention was paid to network neutrality and to insure that the protection layer it promises is effective and cannot be abused. In this paper we develop a theory of Programmed Self-Destruction of crypto currencies. We observe that most crypto currencies have mandated abrupt and sudden transitions. These affect their hash rate and therefore their protection against double spending attacks which we do not limit the to the notion of 51% attacks which is highly misleading. In addition we show that smaller bitcoin competitors are substantially more vulnerable. In addition to small hash rate, many bitcoin competitors mandate incredibly important adjustments in miner reward. We exhibit examples of 'alt-coins' which validate our theory and for which the process of programmed decline and rapid self-destruction has clearly already started.
Privacy is of the utmost importance in genomic matching. Therefore a number of privacy-preserving protocols have been presented using secure computation. Nevertheless, none of these protocols prevents inferences from the result. Goodrich has shown that this resulting information is sufficient for an effective attack on genome databases. In this paper we present an approach that can detect and mitigate such an attack on encrypted messages while still preserving the privacy of both parties. Note that randomization, e.g.~using differential privacy, will almost certainly destroy the utility of the matching result. We combine two known cryptographic primitives -- secure computation of the edit distance and fuzzy commitments -- in order to prevent submission of similar genome sequences. Particularly, we contribute an efficient zero-knowledge proof that the same input has been used in both primitives. We show that using our approach it is feasible to preserve privacy in genome matching and also detect and mitigate Goodrich's attack.
Canadian courts use simple probability reasoning inconsistently in personal injury litigation, subjecting litigants to irregular legal principles and potentially improper compensation. Turning to foundational principles of tort litigation, I suggest a new framework for the availability of simple probability that would promote greater coherence. Simple probability reasoning is understood as an alternative standard of proof that enables compensation for a loss proportional to the likelihood that the loss will occur. Accordingly, the availability of simple probability is thought to depend on which types of facts (past vs. future vs. hypothetical facts) are amenable to balance of probabilities proof versus simple probability. This is the ‘type of fact’ framework, but it is not applied consistently. Part 1 argues that the inconsistency is rooted in the mischaracterization of simple probability reasoning as a standard of proof. It is better conceived of as a method of enabling chances, in their own right, to become legally relevant facts. Understood this way, simple probability is available only where chances are relevant to the legal determination at stake. I apply this characterization in Part 2, concluding that while simple probability reasoning is irrelevant to liability determinations, it is crucial in appropriately assessing damages.
Elites often use social policies to garner political support and ensure regime survival, but social policies are not a silver bullet. Using two waves of Chinese national surveys, I find that a recent policy of abolishing school fees has significantly increased citizens’ demand for greater government responsibility in financing compulsory education. I argue that policy awareness, rather than policy benefits, drives citizens’ demand. Finally, I show that policy awareness has enhanced citizens’ trust in China's central government, but not in local governments. This asymmetry in regime support has two sources—the decentralization of education provision and biased media reporting—which induce citizens to credit the central government for good policy outcomes. Given that citizens’ responses are primarily influenced by policy awareness that is promoted by the state media, this study casts doubt on the use of social policies to sustain long-term political support.
Nesrine Kaaniche, Ethmane El Moustaine, Maryline Laurent
Recent technological advances have given rise to the popularity and success of cloud storage. However, the prospect of outsourcing an increasing amount of data to a third party and the abstract nature of the cloud foster the proliferation of security and privacy challenges, namely, the remote data possession checking. This paper addresses this critical security concern, when storing sensitive data in a cloud storage service, and the need for users to trust commercial cloud providers. It proposes a deterministic Proof of Data Possession (PDP) scheme based on Interactive Proof System(IPS) and an original usage of the GPS scheme. Our approach has several advantages. First, it supports public verifiability which releases data owners from the burden of a periodical verification. Second, it provides constant communication complexity, where the exchanged messages between the storage server and the client are composed of constant number of group elements. Third, our solution is efficient and provably secure, as it is resistant to the fraudulence of the prover and the leakage of verified data.
Andrew Miller, Ari Juels, Elaine Shi, Bryan Parno · 5 authors
Bit coin is widely regarded as the first broadly successful e-cash system. An oft-cited concern, though, is that mining Bit coins wastes computational resources. Indeed, Bit coin's underlying mining mechanism, which we call a scratch-off puzzle (SOP), involves continuously attempting to solve computational puzzles that have no intrinsic utility. We propose a modification to Bit coin that repurposes its mining resources to achieve a more broadly useful goal: distributed storage of archival data. We call our new scheme Perm coin. Unlike Bit coin and its proposed alternatives, Perm coin requires clients to invest not just computational resources, but also storage. Our scheme involves an alternative scratch-off puzzle for Bit coin based on Proofs-of-Retrievability (PORs). Successfully minting money with this SOP requires local, random access to a copy of a file. Given the competition among mining clients in Bit coin, this modified SOP gives rise to highly decentralized file storage, thus reducing the overall waste of Bit coin. Using a model of rational economic agents we show that our modified SOP preserves the essential properties of the original Bit coin puzzle. We also provide parameterizations and calculations based on realistic hardware constraints to demonstrate the practicality of Perm coin as a whole.
Dieudonne Alemagi, Peter A. Minang, Mireille Feudjio, Lalisa Duguma
Cameroon has been a keen participant in Reducing Emissions from Deforestation and Forest Degradation plus conservation, sustainable management of forests and enhancement of carbon stocks (REDD+) negotiations since 2005 and has engaged in activities to enhance the implementation of REDD+. This article reviews progress on REDD+ readiness in Cameroon based on a multiple REDD+ functions framework. Results show that some progress has been made in terms of planning and coordination, institutional development, and the development of some REDD+ projects. Absence of a legal framework, inadequate procedures for stakeholder participation, slow progress in the development of a national strategy, monitoring, reporting, and verification (MRV) challenges, and weak financing remain prominent constraints. Despite having one of the slowest REDD Readiness Preparation Proposal (R-PP) processes in the Congo Basin, stakeholders feel strong ownership because the R-PP was done almost entirely by Cameroonian experts. Some opportunities for improving REDD+ can be considered going forward, including the establishment of procedures for a broader participatory process, speeding up the operationalization of the National Observatory on Climate Change, making use of the ongoing forestry law reform, consideration of a carbon concessions concept, tapping from international initiatives to build on MRV, and improving benefit sharing and financing through the development of an appropriate and decentralized mechanism. Enhancing these opportunities is fundamental for successful REDD+ implementation in Cameroon.Policy relevanceThis article offers a new multidimensional approach to assessing the REDD+ readiness process in Cameroon. This critical assessment, which is done using six key functions, provides an opportunity for enhanced understanding of the process by policy makers, decision makers, and professionals with a view to enabling improvements in the readiness process. Furthermore, the article proffers a series of opportunities that the government and other relevant stakeholders can capitalize on to overcome current hurdles affecting the REDD+ readiness process. It is hoped that policy makers driving the REDD+ process in Cameroon will be able to incorporate the findings of this research into their strategic policy, formulated to advance the REDD+ readiness process. More importantly, it is hoped that the multidimensional framework applied in this study could be useful for assessing REDD+ in similar contexts in the Congo Basin.
Open access
Conservation, Biodiversity, and Resource Management
Quantum zero-knowledge proofs and quantum proofs of knowledge are inherently\ndifficult to analyze because their security analysis uses rewinding. Certain\ncases of quantum rewinding are handled by the results by Watrous (SIAM J\nComput, 2009) and Unruh (Eurocrypt 2012), yet in general the problem remains\nelusive. We show that this is not only due to a lack of proof techniques:\nrelative to an oracle, we show that classically secure proofs and proofs of\nknowledge are insecure in the quantum setting.\n More specifically, sigma-protocols, the Fiat-Shamir construction, and\nFischlin's proof system are quantum insecure under assumptions that are\nsufficient for classical security. Additionally, we show that for similar\nreasons, computationally binding commitments provide almost no security\nguarantees in a quantum setting.\n To show these results, we develop the "pick-one trick", a general technique\nthat allows an adversary to find one value satisfying a given predicate, but\nnot two.\n
Quantum zero-knowledge proofs and quantum proofs of knowledge are inherently difficult to analyze because their security analysis uses rewinding. Certain cases of quantum rewinding are handled by the results by Watrous (SIAM J Comput, 2009) and Unruh (Eurocrypt 2012), yet in general the problem remains elusive. We show that this is not only due to a lack of proof techniques: relative to an oracle, we show that classically secure proofs and proofs of knowledge are insecure in the quantum setting. More specifically, sigma-protocols, the Fiat-Shamir construction, and Fischlin's proof system are quantum insecure under assumptions that are sufficient for classical security. Additionally, we show that for similar reasons, computationally binding commitments provide almost no security guarantees in a quantum setting. To show these results, we develop the "pick-one trick", a general technique that allows an adversary to find one value satisfying a given predicate, but not two.
Housing decentralization not only positions housing sector as regional obligatory, but also triggerspublic expectations upon the improvement of housing conditions. Various weaknesses of centralizedsystem that full of generalization in housing policy makes decentralized system is interpreted as aninnovative renewal process. However, the central government still does a lot of intervention towardhousing program. Limitation happens to local government such as limitation in housing finance,weakness in coordination ability, and less established of local bureaucracy makes intervention fromcentral government in housing program financed by APBN always dominates. The least contributionfrom local government on public housing sector in decentralization era creates paradox. It is caused bythe Ministry of Public Housing (Kemenpera) that cannot perform fully as substitutional institution rolein managing housing in local area. Kemenpera position as ministerial cluster 3 makes them does nothave representative office in local area. Thus, there will be potential of a repeat experience in the past, inform of generalization in housing policy, that complicates the housing problems itself.