We consider zero-knowledge proofs, a class of cryptographic protocols by which an agent (a Prover) can prove to another agent (a Verifier) that a statement is true without revealing any additional information. For example, a zero-knowledge proof allows one to prove knowledge of a password to somebody at the other end of the communication without actually revealing the password. \nWe present an introduction to and survey literature on zero-knowledge proofs, covering the history, formal definition, and classical applications of zero-knowledge proofs. In addition, we consider connections to complexity, demonstrating that all problems in the complexity class NP have zero-knowledge proofs, and also discuss more exotic applications of zero-knowledge, namely in electronic voting and nuclear disarmament. \nWe then consider applications of zero-knowledge to financial regulation, specifically in balancing transparency and confidentiality in financial reporting. Namely, we polled professionals in the financial industry to identify three major classes of regulatory problems. We then utilize zero-knowledge proofs to develop and present cryptographic protocols/mechanisms and solutions to these regulatory problems: (1) An employer verifying an employee has no financial holdings on a blacklist without revealing the other (allowed) holdings of the employee, (2) A fund convincing its investors that its holdings subscribe to particular risk constraints, without disclosing the actual holdings, (3) A collection of investors of a fund verifying aggregate information provided by the fund, while preserving pairwise anonymity. Applications (1) and (3) are novel applications developed in this paper, while (2) is drawn from [47].
Fadhel Ayed, Marco Battiston, Federico Camerlenghi, Stefano Favaro
Given $n$ samples from a population of individuals belonging to different types with unknown proportions, how do we estimate the probability of discovering a new type at the $(n+1)$-th draw? This is a classical problem in statistics, commonly referred to as the missing mass estimation problem. Recent results by Ohannessian and Dahleh \citet{Oha12} and Mossel and Ohannessian \citet{Mos15} showed: i) the impossibility of estimating (learning) the missing mass without imposing further structural assumptions on the type proportions; ii) the consistency of the Good-Turing estimator for the missing mass under the assumption that the tail of the type proportions decays to zero as a regularly varying function with parameter $α\in(0,1)$. In this paper we rely on tools from Bayesian nonparametrics to provide an alternative, and simpler, proof of the impossibility of a distribution-free estimation of the missing mass. Up to our knowledge, the use of Bayesian ideas to study large sample asymptotics for the missing mass is new, and it could be of independent interest. Still relying on Bayesian nonparametric tools, we then show that under regularly varying type proportions the convergence rate of the Good-Turing estimator is the best rate that any estimator can achieve, up to a slowly varying function, and that minimax rate must be at least $n^{-α/2}$. We conclude with a discussion of our results, and by conjecturing that the Good-Turing estimator is an rate optimal minimax estimator under regularly varying type proportions.
We propose definitions and implementations of "S-money" - virtual tokens designed for high value fast transactions on networks with relativistic or other trusted signalling constraints, defined by inputs that in general are made at many network points, some or all of which may be space-like separated. We argue that one significant way of characterising types of money in space-time is via the "summoning" tasks they can solve: that is, how flexibly the money can be propagated to a desired space-time point in response to relevant information received at various space-time points. We show that S-money is more flexible than standard quantum or classical money in the sense that it can solve deterministic summoning tasks that they cannot. It requires the issuer and user to have networks of agents with classical data storage and communication, but no long term quantum state storage, and is feasible with current technology. User privacy can be incorporated by secure bit commitment and zero knowledge proof protocols. The level of privacy feasible in given scenarios depends on efficiency and composable security questions that remain to be systematically addressed.
This article describes how after the concept of anonymous credential systems was introduced in 1985, a number of similar systems have been proposed. However, these systems use zero-knowledge protocols to authenticate users, resulting in inefficient authentication during the stage of proving credential possession. To overcome this drawback, this article presents a signature scheme that uses partially blind signatures and chameleon hash functions such that both the prover and verifier achieve efficient authentication. In addition to providing a computational cost comparison table showing that the proposed signature scheme achieves a more efficient credential possession proving compared to other schemes, concrete security proofs are provided under a random oracle model to demonstrate that the proposed scheme satisfies the properties of anonymous credentials.
Zahra Zahedi, Mohammad Mehdi Arefi, Alireza Khayatian, Hamidreza Modares
In this paper, a solution for Nash equilibrium seeking problem for N-players static non-cooperative games with non-quadratic payoff functions is proposed. The proposed solution is a non-model based approach, in the sense that the players do not need any knowledge about the agent's model or other players' actions, and can attain the Nash equilibrium using only measurements of payoff values. To overcome the shortcoming of existing non-model based algorithms, for which the Nash equilibrium stays within a small neighborhood and oscillates, the proposed approach adjusts the classical extremum seeking algorithms so that the amplitude of excitation sinusoidal signal converges to zero locally and exponentially. Therefore, with removing steady-state oscillation, not only the deleterious effects of steady-state oscillation is eliminated but also Nash equilibrium is achieved faster. The details of proof and the analysis for stability and convergence are provided. Finally, the efficiency and effectiveness of the algorithm are illustrated with a numerical example and simulation.
Proposed cryptographic protocol with zero-knowledge proof on elliptic curves using one-way hash function, allowing to establish the truth of allegation and does not convey any additional information about the approval. Cryptographic protocols based on zero-knowledge proof allow identification, key exchange and other cryptographic operations to be performed without leakage of sensitive information during the information exchange. The implementation of the cryptographic protocol of the zero-knowledge proof on the basis of the mathematical apparatus of elliptic curves allows to significantly reduce the size of the protocol parameters and increase the cryptographic stability (computational complexity of the hacking problem). The security of cryptosystems on elliptic curves is based on the difficulty of solving the elliptic curve discrete logarithm problem. The completeness and correctness of the protocol is determined in the work, an example of calculation is given, the cryptographic protocol is modeled on the High-Level Protocol Specification Language, the model validation and verification of the protocol are performed. Software verification of the cryptographic protocol was performed using the software modules On the Fly Model Checker and Constraint Logic based Attack Searcher. To validation the cryptographic protocol for resistance to intruder attacks was used the Security Protocol Animator package for Automated Validation of Internet Security Protocols and Applications. The security of the proposed cryptographic protocol is based on the difficulty of solving the elliptic curve discrete logarithm problem and the cryptographic stability of the hash function. To implement the cryptographic protocol, you can use the recommended elliptical curves according to DSTU 4145-2000 and the hash function GOST 34.311-95.
We propose building a new PKC in a ring structure, the classification of rings being an open problem. The difficulty of the scheme is based on retrieving the eigenvalues of endomorphism on a finite type module over a non-commutative ring. It is resistant to a chosen cipher text attack. Working in the fraction ring of a non-commutative ring makes our scheme a zero-knowledge proof of knowledge, result indistinguishable, in the Naor-Yung model. Finally, a dramatic improvement in security is obtained through the drawing with uniform probability of the working ring at high frequency.
The prevalence of IoT devices makes them an ideal target for attackers. To\nreduce the risk of attacks vendors routinely deliver security updates (patches)\nfor their devices. The delivery of security updates becomes challenging due to\nthe issue of scalability as the number of devices may grow much quicker than\nvendors' distribution systems. Previous studies have suggested a permissionless\nand decentralized blockchain-based network in which nodes can host and deliver\nsecurity updates, thus the addition of new nodes scales out the network.\nHowever, these studies do not provide an incentive for nodes to join the\nnetwork, making it unlikely for nodes to freely contribute their hosting space,\nbandwidth, and computation resources. In this paper, we propose a novel\ndecentralized IoT software update delivery network in which participating nodes\nreferred to as distributors) are compensated by vendors with digital currency\nfor delivering updates to devices. Upon the release of a new security update, a\nvendor will make a commitment to provide digital currency to distributors that\ndeliver the update; the commitment will be made with the use of smart\ncontracts, and hence will be public, binding, and irreversible. The smart\ncontract promises compensation to any distributor that provides\nproof-of-distribution, which is unforgeable proof that a single update was\ndelivered to a single device. A distributor acquires the proof-of-distribution\nby exchanging a security update for a device signature using the Zero-Knowledge\nContingent Payment (ZKCP) trustless data exchange protocol. Eliminating the\nneed for trust between the security update distributor and the security\nconsumer (IoT device) by providing fair compensation, can significantly\nincrease the number of distributors, thus facilitating rapid scale out.\n
Andrei Yu. Khrennikov, Sergei V. Kozyrev, W. A. ZĂșñiga-Galindo
Introduction The connections between the Archimedean heat equations with number theory and geometry are well known and deep. Let us mention here the connection with the Riemann zeta function which leads naturally to trace-type formulae, see e.g. [48] and the references therein, and the connection with the AtiyahâSinger index theorem, see e.g. [178] and the references therein. The study of non-Archimedean counterparts of the above-mentioned matters is quite relevant, especially taking into account that the Connes and Deninger programs to attack the Riemann hypothesis lead naturally to these matters, see e.g. [112], [121], [309] and the references therein. For instance, several types of p -adic trace formula have been studied, see e.g. [13], [96], [449] and the references therein. In this chapter we study heat traces and spectral zeta functions attached to certain p -adic Laplacians, denoted as A ÎČ , following [105]. Using an approach inspired by the work of Minakshisundaram and Pleijel, see [340]â[342], we find a formula for the trace of the semigroup e â tAÎČ acting on the space of square integrable functions supported on the unit ball with average zero, see Theorem 12.13. The trace of e â t A ÎČ is a p -adic oscillatory integral of Laplaceâtype. We do not know the exact asymptotics of this integral as t tends to infinity; however, we can obtain a good estimation for its behavior at infinity, see Theorem 12.13 (ii). Several unexpected mathematical situations occur in the p -adic setting. For instance, the spectral zeta functions are p -adic Igusa-type integrals, see Theorem 12.18. The p -adic spectral zeta functions studied here may have infinitely many poles on the boundary of their domain of holomorphy. Thus, to the best of our knowledge, the standard Ikehara Tauberian theorems cannot be applied to obtain the asymptotic behavior for the function encompassing the eigenvalues of A ÎČ less than or equal to T â„ 0. However, we are still able to find good estimates for this function, see Theorem 12.18, Remark 12.19, and Conjecture 12.20. The proofs require several results on certain âboundary-value problemsâ attached to p -adic heat equations associated with operators A ÎČ , see Proposition 12.5, Theorem 12.11, and Proposition 12.12.
Fergus Dall, Gabrielle De Micheli, Thomas Eisenbarth, Daniel Genkin · 7 authors
Intel Software Guard Extensions (SGX) allows users to perform secure computation on platforms that run untrusted software. To validate that the computation is correctly initialized and that it executes on trusted hardware, SGX supports attestation providers that can vouch for the userâs computation. Communication with these attestation providers is based on the Extended Privacy ID (EPID) protocol, which not only validates the computation but is also designed to maintain the userâs privacy. In particular, EPID is designed to ensure that the attestation provider is unable to identify the host on which the computation executes. In this work we investigate the security of the Intel implementation of the EPID protocol. We identify an implementation weakness that leaks information via a cache side channel. We show that a malicious attestation provider can use the leaked information to break the unlinkability guarantees of EPID. We analyze the leaked information using a lattice-based approach for solving the hidden number problem, which we adapt to the zero-knowledge proof in the EPID scheme, extending prior attacks on signature schemes.
Edgar GonzĂĄlez FernĂĄndez, Guillermo Morales-Luna, FeliĂș Sagols Troncoso
Zero-Knowledge Proofs ZKP provide a reliable option to verify that a claim is true without giving detailed information other than the answer. A classical example is provided by the ZKP based in the Graph Isomorphism problem (GI), where a prover must convince the verifier that he knows an isomorphism between two isomorphic graphs without publishing the bijection. We design a novel ZKP exploiting the NP-hard problem of finding the algebraic ideal of a multivariate polynomial set, and consequently resistant to quantum computer attacks. Since this polynomial set is obtained considering instances of GI, we guarantee that the protocol is at least as secure as the GI based protocol.
In the 1980s, Deirdre McCloskey argued that economists should look beyond their mathematical formulas and their positivist methodologies. If âeconomic style appeals in various ways to an ethos worthy of belief,â then economists should âgive up their quaint modernism and open themselves to a wider range of discourse⊠. [They should] examine their language in action and converse more politely with others in the conversation of humanityâ (McCloskey Rhetoric, 11, 167). Much broader than her original ârhetoric of economics,â McCloskeyâs recent âhumanomics,â asks us to consider cultural as well as economic forces when investigating human prosperity (Bourgeois, 553â559). McCloskeyâs humanomics is one example of the rhetoric of economics clearing the way for new scholarly efforts in the social sciences. The articles in this special collection move in another direction, towards rhetorical analysis and historical inquiry. Like McCloskeyâs humanomics, the historical inquiry into rhetoric and economics is a worthy sequel to McCloskeyâs pioneering efforts.Robert McDonaldâs âFrom âIncentive Furieâ to âIncentives to Efficiency,â or the Movement of âIncentiveâ in Neoclassical Thought,â for instance, rhetorically analyzes works by Jeremy Bentham, Alfred Marshall, and Paul Samuelson. Echoing McCloskeyâs rhetoric of economics, McDonald suggests a modest disciplinary conclusion about the rhetorical constitution of economic science. He notes the âpoeticalâ quality of incentives, their âcall to act rationally,â and their rhetorically objectified constitution as âthe desired object that provides the key to unlocking a universal analysis of social realityâ (this issue). But, instead of drawing conclusions about the discipline of economics or rhetoricâs economic function, McDonald asks: What does poetically constituted âincentiveâ do in our common conversations and our daily deliberations? The ârhetoric of economicsâ was a critical inquiry, part of the larger Project on the Rhetoric of Inquiry that McCloskey and others began (1980) at the University of Iowa. McCloskeyâs humanomics is a human science including cultural criticism, philosophical rumination, and statistical formulas. McDonaldâs critical analysis of economic arguments is an historical inquiry into the local constitution and the specific function of public discourse. Like McDonald, the authors featured in this special issue share McCloskeyâs two key insights. We all agree that economics is rhetorically constituted, and rhetoric is economically effective. But we attend to specific arguments, their rhetorical form, and their historical function.McDonaldâs essay traces a common rhetorical turn across two centuries of argumentation. The first major segment of his argument explores the etymology of âincentive,â showing that the anthimeric movement from adjective to noun happened simultaneously in university hallways and vulgar conversations. Samuelson wasnât the only twentieth-century voice chattering about âincentives.â We all were. McDonaldâs etymology follows the evolution of a rhetorical commonplace. His analysis highlights its social effects: âthe supersession of society by the economyâ (this issue). He concludes with a question about contemporary policies. â[W]hat is repressed, negated, and transformed when incentives become a universal objectâ? (this issue).McDonaldâs âincentiveâ has a centuries-old pedigree. Other topics of economic argumentation seem less senescent. In his contribution to this special issue, William O. Saas charts an important shift in U.S. presidential rhetoric: from the Keynesian definition of federal debt (a way to support publicly favored economic initiatives) to the neoliberal definition of a balanced budget (an eternal moral good, irrespective of federal obligations or economic imperatives). The analogy between the U.S. federal budget and a familyâs finances became widespread during national conversations about Reaganite supply-side economics. The âpump primingâ and âprinting moneyâ metaphors (both describing federal deficit spending during a recession) seem no older than the Federal Reserve System (1913). Yet the lines of argument that Saas analyzes have a long history.Writing in 1695, Secretary to the Treasury of Great Britain under William III, William Lowndes bickered with mercantilists who defined the balance of trade as a moral good. They further opposed revaluation of English specie (the early-modern version of âprinting moneyâ) on the grounds that such an action would lead to inflation. Mercantilists believed that Englandâs monetary problems could only be rectified by correcting the balance of trade and attracting foreign silver to English shores. Lowndes conceded his opponentsâ definition, allowing that âthe Ballance [sic] of Trade must be Rectifiedâ (91). Exactly ten years later, based on a proto-Keynesian definition of federal debt, John Law (of Mississippi Company fame) suggested that the Scottish government allow monetization of land titles, essentially âprinting moneyâ to spur domestic industry. According to Law, â[a]n addition to the money adds to the value of the country, so long as money gives interest, it is imployed [sic]; and money imployed brings profitâ (21â22). There are some important differences, of course, between the twentieth-century arguments that Saas analyzes and their seventeenth-century analogues. Saas looks at the Reaganite argument that a balanced budget, not balanced trade, is a moral good. And John Law may have presaged the Keynesian pump-priming metaphor, but he did not take the argument as far as the neo-Keynesians whom Saas favors. Nonetheless, this quick comparison shows a line of economic rhetoric stretching from seventeenth-century monetary arguments to twentieth-century fiscal disagreements.I do not have to demonstrate a storied legacy for the economic arguments that William Rodney Herring analyzes because he starts in the early eighteenth century. Herringâs historical scope aside, âNeither Pistols nor Sugar-Plumbs: The Rhetoric of Finance and the 1720 Bubblesâ offers something else to the study of economic rhetoric: an attention to financial instruments as persuasive devices. Herring claims that early eighteenth-century offers to buy stocks at rates above or below par (face-value, as distinct from market value) were a kind of symbolic action, an effort to influence buyersâ choices by changing their perceptions. Herringâs contribution is twofold. In an analytical register, he contends that financial instruments themselves are rhetorical. In an historical register, he notes that financial instruments have historically held a rhetorical function. His analysis leads to contemporary political questions, not unlike those raised by McDonald and Saas. Herring asks, What persuasive force do financial instruments exert? McDonald ponders, How did Benthamâs anthimeria change into Samuelsonâs common sense? Saas wonders, How have we defined credit and debt? While exploring common lines of economic argumentation, some explicitly discursive and others implicitly persuasive, all three articles indulge a wide historical scope and allow some political reflection.The remaining three articles in this collection, by contrast, present robust political implications supported by some historical reflection. The shared mix of history and advocacyâinquiry and argumentâcharacterizes the new historical inquiry into rhetoric and economics.Joshua S. Hanan and Jeffrey St. Onge discuss the common antithesis between Wall Street and Main Street in their analysis of the 2015 movie The Big Short. Hanan and St. Onge point to a more fundamental antithesis between the oikos and the polis, arguing that the ancient Greeks privileged the polis, seeing the oikos as a âsupplementary backgroundâ and the polis as âa sovereign domain of actionâ (this issue). Their genealogical inquiry reveals that moderns have reconfigured this order. The metonymic âMain Streetâ recedes into the background, while âWall Streetâ becomes a âsphere of emergent freedom and autarkyâ (this issue). Hanan and St. Onge scrutinize an antithesis, adulating one economic class and its privileged sphere of activity while relegating the other to inconsequence.Such rhetorical antithesis, however, is neither peculiar to present-day finance, nor specific to modish Hollywood. Two moments remind us that the antithesis discussed by Hanan and St. Onge can be found in the infancy and midlife of modern economic argumentation. In late seventeenth-century England, land-owning gentry imagined their agricultural sphere as the productive arena where political action should take place, and they sneered at new financiers who invented financial instruments such as the Million Lottery Act and the Bank of England (1694). Like many English mercantilists and French Physiocrats, John Briscoe assumed that the truly âproductiveâ sphere was agriculture, so the empowered political class should be the noble âLanded-Men,â not the usurious âmonied-menâ (19). He juxtaposed a privileged, agricultural, and aristocratic polis against the nonproductive (financial) oikos. Briscoeâs argument is classical in form, repeated through the ages, separating a productive from an unproductive sphere and depending on class interest. Two-and-a-half centuries later, John Maynard Keynes argued that global bankers had become a privileged class, global finance a dominant polis, to the detriment of the industrial oikos. Like the Wall Street/Main Street opposition, Keynesâs rentier/producer antithesis asserts an injustice, this time with the rentier unfairly in the privileged sphere and the manufacturer all but erased. According to Keynes, gradually eliminating interest (making âcapital goods so abundant that the marginal efficiency of capital is zeroâ), would likewise eliminate âmany of the objectionable features of capitalism.â Full employment would result from low (effectively zero) interest rates. The ârentier,â no longer able to make a living, would vanish. Entrepreneurial industrialists would become the properly privileged class. â[T]here would still be room ⊠for enterprise and skill in the estimation of prospective yieldsâ (221), so industry would become the new polis.I point to a long history behind the antithesis that Hanan and St. Onge locate in their contemporary analysis. But I want to emphasize that they find something more than a tired rhetorical juxtaposition of warring classes. Their genealogy explains that rhetorical activity is invested in the privileged polis (Wall Street) while the ambient background of necessity (Main Street) remains. They are analyzing an old trope while explaining its new turn, its contemporary economic effects. They add a new awareness: the dialectical structure of the oikos and the polis (Main Street and Wall Street) excludes the oikos; the rhetorical form diminishes Main Streetâs agency. Something similar can be said about the topics discussed in Catherine Chaputâs and Crystal Broch Colombiniâs articles. While Chaput and Colombini seek out old lines of economic argumentation, they find much more than tired commonplaces applied to present circumstances.Chaput and Colombini analyze supplemental arguments that shore up the economistâs dryly rational proof. Again, the historical precedence is not hard to find. Thomas Malthusâ demographic arguments inspired Thomas Carlyleâs oft-repeated characterization of economics: âthe dismal science.â Harriet Martineau supplemented Malthusâs tomes about cyclical overpopulation and famine. She created characters who embodied rational prudence while suffering economic hardship. In one of Martineauâs Illustrations of Political Economy (1832â1834), Ella of Garveloch, a rich literary character, wisely steers her family through a wretched famine. Surrounded by suffering, she proclaims, in terms far more convincing than anything Malthus ever mouthed, âEvil is palliated by the caution of the prudent, by the emigration of the enterprising, and by other means which may yet remainâ (102). Martineauâs characters are ethical arguments about how people should behave once they understand rational principles, such as âthe operation of the principle of increase within narrow boundsâ (Martineau 103). Ayn Rand, writing a century later, offered pathetic appeals to supplement the arid libertarian arguments of Ludwig von Mises and Friedrich Hayek. Rand even theorized the necessity of her pathetic supplement, saying that her nakedly pro-capitalist novels were meant to emotionally convey a âsense of lifeâ to a reader who would then induce âan intense, profoundly personal ⊠value-meaning,â a meaning that might be deduced rationally but without the force of conviction (35). We could reason our way toward a belief in the free market, said Rand, or we could gaze upon the âartistâs view of manâ (67), a sculpted Howard Roark or a daring Dagny Taggart. Rand and Martineau shared the belief that pathetic and ethical argumentation supplements rational economic deduction. Colombiniâs and Chaputâs analyses present the ethical and the emotional appeals as not merely supplemental to the economic claim but rather as integral to the political economy.Colombini analyzes a moral argument commonly repeated during the recent housing market collapse. As she explains, the economistâs wholly rational definition of âstrategic defaultâ explains why a prudent person possessing an underwater mortgage should simply forfeit the property. But such rational action, if widespread, would harm banks and might cripple the financial sector. As a result, in public discourse, an ethically supplemental definition was added: Mortgage holders were said to be âwalking awayâ from their homes and their responsibilities. The Martineau and Rand examples suggest that economic arguments require an ethical and pathetic sugarcoating to sweeten the rational pill. Colombiniâs analysis of âwalking awayâ suggests that the supplement is more than decoration. Without these moral public arguments, ârationalâ neoliberalism would not function. Rendered unpersuasive by its own cold ratiocination and unsustainable by its victimsâ rational actions, neoliberalism depends upon the rhetorical strategies that Colombini discusses.Chaput explores Donald Trumpâs economic arguments. She explains that an irrational and inconsistent Trumponomics mobilizes affect, that fluttery sensitivity and jittery responsivity energized by social media, image ads, and wearable technology. Working âalong ontological axes,â Chaput illuminates a new pathetic appeal in a new rhetorical role (this issue). Trumpâs pathos does not supplement his rational appeal. His affect is the argument. The âepistemic focus of the rhetoric of economic argumentsâ emphasized logos. Chaput picks up where McCloskey left off, by analyzing the affectively suasive dimension. Understanding affect requires Chaputâs âontological focusâ (this issue). Rand and Martineau offered ethical and pathetic supplements. Colombini and Chaput theorize ethical and pathetic economics. Aristotle once observed that rhetoric must appeal to the whole person. Chaput and Colombini suggest that our present-day economy enlists every felt conviction and mobilizes every bodily corpuscle. Like all persuasive efforts, rational economic theory requires ethical and pathetic appeals. Colombini and Chaput add to the classical maxim a contemporary reflection: Economic systems cannot survive without economic argumentation. Chaput directly states this when remarking that the neoliberal economy itself, like Trumpâs zigzagging affective appeals, ânot only moves in a decidedly nonlinear path, it produces a bodily thinkingâ (this issue). Affect is not just a rhetorical appeal; itâs a bio-political factory and an economic engine.At the twentieth centuryâs close, Deirdre McCloskey averred that the rhetoric of economics was not âintrinsically revolutionary or intrinsically conservativeâ (Knowledge 339). Her last and longest book, before the bourgeois virtue trilogy, circled back to a methodological conclusion: âPerhaps the time has come, after a useful childhood spent in positivism, for economists to grow up tooâ (Knowledge 396). While the authors featured in this special issue often separate their approach to economic rhetoric from McCloskeyâs rhetoric of economics, they all owe her a significant debt. Once she had cleared the positivist brush, other inquiries, such has her humanomics, could take seed. Like McCloskeyâs initial and most recent program, the articles in this special issue require neither a neo-Marxian nor a neo-Keynesian tilt. Nonetheless, the historical analysis of economic rhetoric requires that we engage politics. Two decades ago, when she proclaimed her partisan neutrality, McCloskey was dodging typical accusations of postmodern relativism and radical nihilism, the alleged epistemological bedfellows of socialism, communism, and anarchism. Critically analyzing economic arguments can similarly avoid a partisan but not a political tilt. Historically situating and tracing economic arguments recalls an older paradigmâpolitical economyâa paradigm that refused to separate public discourse from social science or partisan bickering from expert advice. In this introduction, I have argued that all the arguments analyzed in this special issue have long historical traditions. But more than these traditions of economic argumentation, the refusal to throw out the political baby with the positivist bathwater makes the contributions to this special issue properly rhetorical, fully humanist, and thoroughly historical.
Several popular cryptocurrencies incorporate privacy features that "mix" real transactions with cover traffic in order to obfuscate the public transaction graph. The underlying protocols, which include CryptoNote and Monero's RingCT, work by first identifying a real transaction output (TXO), sampling a number of cover outputs, and transmitting the entire resulting set to verifiers, along with a zero knowledge (or WI) proof that hides the identity of the real transaction. Unfortunately, many of these schemes suffer from a practical limitation: the description of the combined input set grows linearly with size of the anonymity set. In this work we propose a simple technique for efficiently sampling cover traffic from a finite (and public) set of known values, while deriving a compact description of the resulting transaction set. This technique, which is based on programmable hash functions, allows us to dramatically reduce transaction bandwidth when large cover sets are used.We refer to our construction as a recoverable sampling scheme, and note that it may be of independent interest for other privacy applications. We present formal security definitions; prove our constructions secure; and show how these constructions can be integrated with various currencies and different cover sampling distributions.
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
The Internet of Things (IoT) network of connected devices currently contains more than 11 billion devices and is estimated to double in size within the next four years. The prevalence of these devices makes them an ideal target for attackers. To reduce the risk of attacks vendors routinely deliver security updates (patches) for their devices. The delivery of security updates becomes challenging due to the issue of scalability as the number of devices may grow much quicker than vendors' distribution systems. Previous studies have suggested a permissionless and decentralized blockchainbased network in which nodes can host and deliver security updates, thus the addition of new nodes scales out the network. However, these studies do not provide an incentive for nodes to join the network, making it unlikely for nodes to freely contribute their hosting space, bandwidth, and computation resources. In this paper, we propose a novel decentralized IoT software update delivery network in which participating nodes (referred to as distributors) are compensated by vendors with digital currency for delivering updates to devices. Upon the release of a new security update, a vendor will make a commitment to provide digital currency to distributors that deliver the update; the commitment will be made with the use of smart contracts, and hence will be public, binding, and irreversible. The smart contract promises compensation to any distributor that provides proof-of-distribution, which is unforgeable proof that a single update was delivered to a single device. A distributor acquires the proof-of-distribution by exchanging a security update for a device signature using the Zero-Knowledge Contingent Payment (ZKCP) trustless data exchange protocol. Eliminating the need for trust between the security update distributor and the security consumer (IoT device) by providing fair compensation, can significantly increase the number of distributors, thus facilitating rapid scale out.
Authentication over insecure public networks or with untrusted servers raises more concerns in privacy and security.Modern algebra is one of the significantfields of mathematics. It is a combination of techniques used for a variety of applications including the process of the manipulation of the mathematical categories. In addition,modern algebra deals in depth with the study of abstractions such as groups, rings and fields,the main objective of this article is to provide a novel algebraic verification protocol using ring theory. The protocol is blind, meaning that it detects only the identity, and no additional information will be known anything about the prover (the biometric) to the authenticating server or vice-versa. More officially a blind authentication scheme is a cryptographic protocol that comprises of two parties, a user (the prover) that wants to achieve having signs on her messages, and a signer (the verifier) that is in ownership of his secret signing key. In this paper, we employ the algebraic structure called central Armendariz rings to design a neoteric algorithm for zero knowledge proof. The proposed protocol is established and illustrated through numerical example, and its soundness and completeness are proved.This method gave two important properties for the central Armendariz zero knowledge protocol compared with other known protocols.