Blockchain Papers

Kaoru Kurosawa, Swee‐Huay Heng

Abstract. In undeniable signature schemes, zero-knowledgeness and non-transferability have been identified so far. In this paper, by separating these two notions, we show the first 3-move confirmation and disavowal protocols for Chaum’s undeniable signature scheme which is secure against active and concurrent attacks. Our main observation is that while the signer has one public key and one secret key, there exist two witnesses in the confirmation and disavowal proofs of Chaum’s scheme.

Mark Nunes


 
 
 Truth be told, the “Y2K bug” was quite a disappointment. While the technopundits wooed us with visions of network failures worthy of millennial fervor, Jan. 1, 2000, came and went without even a glimmer of the catastrophic. Yet the Y2K “bug” did reveal the degree to which the American apocalypse now took the form of the network itself. The spaces of everyday life in America and elsewhere in a developed world produce and are produced by network structures that Manuel Castells has called “spaces of flow.” As such, Catastrophe today is marked more by dispersion and dissipation, rather than breakdown — a dis-strophe of social forms, structures, and experience. The dissipation of enactive networks does not, however, equate with a system failure. With the Internet “bubble burst” of March, 2000, the very exuberance of market flows were very much the conditions of possibility for both the irruption of a new economy and its sudden evaporation. It is not the ephemerality of these social forms and structures that disorients activities of everyday life in a network society, but rather our lack of control over distributed processes. The bubble burst, then, by no means sounded a death knell for distributed network functions. Rather, it marked a moment of increased misrecognition of the forms, structures, and practices that were the conditions of possibility for the event itself, as an ideology of authentication eclipsed a rhetoric of emergence and flow. Billions in capital disappeared in a matter of weeks, but the network forms and structures that allowed individual users “direct access” to the flows of capital remained in place for a normative virtual class, articulated as personalized and privatized spaces of control. As the bubble burst signaled an instance of digital dis-strophe, the 9/11 attacks on the World Trade Center marked a similar dissipative moment, articulated in the material terror of over 1,300 feet of skyscraper steel and human bodies turned to wreckage and dust. Much as the market crash of 2000 represented a collapse from within of the same network processes that enabled the market’s phenomenal growth, for all the “foreignness” of the terrorists, al Qaeda as an organization appeared decidedly at home in the globalized network society that it threatened to destroy. In an instance of Baudrillardian “ironic revenge,” terrorism appropriated all the trappings of a global space of flows in the name of subverting that same social structure (Baudrillard, “Spirit” 17-19). Only within the conditions of possibility of networked social space could such attacks occur. As such, terrorist cells functioned (the media informed us) as nodes in a distributed network, a human articulation of a space of flows capable of enacting horrifying acts beyond control. While in the years leading up to the market collapse of March, 2000, a growing number of an emerging virtual middle class (from cyberhippy to day-trader manqué) began to understand distributed networks as material expressions of a social revolution, the image of a distributed network changed after 9/11, becoming a global spatiality of fear and danger. As independent scholar Sam Smith notes on his weblog: I expect the organizing principle of the coming age – the era that began on September 12… – will be the distributed network, and we already have some early indications of what this period might look like. The decentralized potency of the Internet is a perfect metaphor in so many ways, and al Qaeda itself provides an apt demonstration of the character and power of the distributed network…. As our ill-prepared military has discovered, it’s hard to kill something you can’t find. Thank goodness for the Taliban, eh? Although figured as an anti-modern fundamentalism, the terrorist networks associated with September 11 served as an image of contemporary network structures themselves. The enemy, it seemed, was not some reclusive figurehead, but rather, the spatiality of the network itself, enacted by distributed, autonomous agents. Carl Conetta, writing on the nature of al Qaeda as a distributed network, notes in particular its ability to “[link] subnational elements together in a transnational web,” to thrive in nation-states that have collapsed or are about to collapse; in short, al Qaeda “lives in the interstices” of modern global space (Conetta). As globalization’s ironic revenge, distributed terror maps the interstitial flows that exploit the inability of centralized authority to coordinate emergent, enactive forms of network agency. In response, the US Congress passed the Patriot Act as an attempt to introduce modes of control into distributed networks and place them at the fingertips of state-based agencies. In an era of global flows, the Patriot Act reestablished the homeland as both a concept of social space and a delimited space of practice, articulated through global network structures. As part of President Bush’s “war on terror,” the Patriot Act declared war on the dispersive and dissipative nature of distributed networks by introducing what Deleuze and Guattari would call state-based apparatuses of capture. But as Deleuze notes, in a world of flows, “capture” occurs as a modulation, not an enclosure — a system of distributed control that is itself expressed in flows (4). The Patriot Act acknowledges networks themselves as modes of agency (noted in its frequent reference to an “intelligence service or network of a foreign power”), and as such institutes a legislative structure to “trap and trace” emergent network structures. In effect, the Patriot Act marks a modulation of networked social space that affirms the primacy of global flows in contemporary life at the same time that it initiates state-based systems of distributed control. Apparatuses of capture modulate flows by eliminating the interstitial and regulating transmission as a mode of order. The “homeland security” measures, then, are precisely this sort of effort to modulate the forms, structures, and practices of a space of flows. As the US military force mounted, one heard less and less talk of the distributed network form of terror, as an uncontrollable threat coalesced in the modulated image of a handful of figureheads: a “line up” in its most literal sense connecting bin Laden, Zakawi, and Hussein. The infamous Most Wanted card deck shifted our imagination from the shuffling networks of global terror to a linear ranking of Ba’ath Party players — a chain of command in a “rogue nation,” from ace of spades to the two of clubs. The topology of fear had changed. Within months, the U.S. government’s rhetoric had swayed our attention from terrorist networks to an “Axis of Evil.” Gone were the references to the complex webbings of distributed systems, and in its place, the reassuringly linear, gravitational orientations of good and evil. The “axis” not only revived the relatively clear lines of geopolitics of the Second World War; it also attempted to reestablish a representation of space predicated upon unidirectional movements and centralized control. Meanwhile, back in the homeland, DARPA’s Total Information Awareness (TIA) Program (renamed the Terrorist Information Awareness Program for better PR) promised a means of capturing flows of information through distributed control over the network. Whereas terrorist organizations exploit the interstitial spaces of a global network society, TIA as a state-based apparatus of capture promised to utilize these same networks to modulate a space of flows and extract orderly patterns of information. The agent of the state doesn’t necessarily control the flow of these networks, but rather, extracts mappings of emergent connections enacted by the network itself. Patterns of informatic exchange and transmission, then, provide distributed control over a network environment that can only be defined by flows and virtualities. In contrast to the data mining we are all used to in a commercial setting, where patterns of aggregate data give rise to “meaningful” market analysis, distributed control systems would instead focus on “rare but significant connections” mapped by the relational structures of a situated subject (DARPA A-14). Lines of contact emerge as pattern recognition allows authorized agents to “connect the dots” (a favored expression throughout DARPA’s report to Congress) within an undifferentiated network of data-flow. Distributed control creates a means for modulating what would otherwise appear as abject noise or aberrant links; the very fact that terrorist networks are represented as abject, interstitial social formations (and vice versa) becomes the condition of possibility for their recognition and capture. In a world in which networks of flows shape both state structures of power and the attempts to destroy those same structures, the lines have been drawn — and modulated. Through systems of distributed control, enactive networks now increasingly speak to a social space in which agency itself maps an emergent network. Less than two years after the Patriot Act was signed into law, DARPA lost Congressional funding for TIA. Again, it was the potential for success that induced our visions of digital catastrophe — that such a large body of data subjected to distributed control presented the potential for the network’s ironic revenge. Yet in many ways the modes of distributed control enacted by networks of pattern recognition are already matters of everyday life, misrecognized as “conveniences” in a network society. While spam filters and software agents hardly equate with the sophistication of TIA programs, the goal of each is the same — to modulate flows and cast off or capture the interstitial within programs of order. While information may want to be free, the forms, structures, and practices of everyday life reveal the degree to which a normative virtual class exerts a will to control, and an ir

A. Saxena

In this paper, we introduce the concept of additive zero knowledge. Essentially, an additive proof can be considered as a proof system involving many provers and one verifier such that the statements of all the provers are proved simultaneously. Our model of additive proofs is presented using constructions of blind group identification, aggregate signatures and chained signatures. The security of our protocols relies on the difficulty of the underlying Diffie-Hellman problem in bilinear maps. As applications, we present a novel method to prevent spam.

Fagen Li, Juntao Gao, Yupu Hu

No abstract is available for this record.

Alexandre Ruiz, Jorge L. Villar

In this paper we propos eas imple PVSS scheme based on the homomorphic properties of Paillier' se ncryption scheme. This ne ws cheme is the first known PVSS scheme based on the decisional composite residuosity assumption. The verification process in this scheme is much simpler than in the other known schemes. Furthermore, in our proposal, verification is made non-interactive without using th eF iat-Shamir technique or an ya dditional Zero Knowledge proof.

Aggelos Kiayias, Antonina Mitrofanova

No abstract is available for this record.

Petros Belsis, Stefanos Gritzalis, Apostolos Malatras, Christos Skourlas · 5 authors

No abstract is available for this record.

Amitabh Saxena, Serguey Priymak, Ben Soh

In identification protocols with public verifier coins (like Fiat-Shamir), a passive adversary watching the communication gains information intended only for the verifier. On the other hand, private coin protocols with fewer than three rounds cannot be zero-knowledge. In this paper, we introduce the notion of bounded-prover zero-knowledge proofs which require only two rounds and can be considered perfectly zero-knowledge under certain intractibility assumptions. Specifically, we exploit the gap between two computational problems to achieve zero-knowledge in a dishonest verifier scenario.

Giovanni Di Crescenzo

No abstract is available for this record.

Randolph N. Jonakait

No abstract is available for this record.

Rehema Mayanja

Decentralization of health services in Uganda, driven by the structural adjustment programme of the World Bank, was embraced by government as a means to change the health institutional structure and process delivery of health services in the country.Arising from the decentralization process, the transfer of power concerning functions from the top administrative hierarchy in health service provision to lower levels constitutes a major shift in management, philosophy, infrastructure development, communication as well as other functional roles by actors at various levels of health care.This study focused its investigation on ways and levels to which the process of decentralization of health service delivery has attained efficient and effective provision of health services.The study also examined the extent to which the shift of health service provision has influenced the role of local jurisdictions and communities.Challenges faced by local government leaders in planning and raising funds in response to decentralized health service delivery were examined.The study used a descriptive survey research design employing qualitative techniques, namely questionnaires, structured interviews, observation, and document analysis to establish the extent to which the decentralized approach to health service delivery has impacted on local governments and the vulnerable target groups such as the rural and urban poor, children, mothers, HIV/AIDS victims, orphans and refugees.Key respondents were government officials in health related management in the country at various levels.Health workers and beneficiaries of health services were interviewed to share their views and experiences of decentralized health care service provision.iii Using a conceptual framework of "Community as Client", the findings illustrate that while some local governments in the country have extended health units closer to some communities, the pursuit of a decentralized health service delivery system in Uganda over-assumed the benefits of decentralizing health care.The observations indicated that health care is not better organized; neither has decentralization provided greater involvement of local communities in mobilization and capacity building of community-based health workers.The acclaimed cost containment and reduction through duplication of services, reduction of inequities, integration of activities of different agencies and organizations involved in health care have not been achieved in concert with original expectations and assumptions of decentralization.These include: strengthened health policy and planning functions of the ministry of health, improved implementation of health programmes, greater community control and financing (ownership) and improved inter-sectoral coordination.From the findings, it would appear that the motivation for decentralizing health care was not intrinsically guided by how the decentralized health system can better serve the poor majorities in the country.The study concludes that the decentralization of health services in Uganda was not matched with commitment for provision of necessary health supplies, and delivery of health care services through a centrally coordinated national network of health facilities.The Ugandan Government in particular Ministry of Health and the government needs to evaluate the achievements and challenges faced by the health care system under decentralization within the broader perspective of health for all, as a means to establish appropriate refocusing of health care delivery for optimal benefit of the client communities.

N. Mungai Lenneiye

This publication, Who has the yam and who has the knife, seeks to illustrate and address the creative tension needed to ensure an equitable distribution of power over the development process, by examining how putting the yam (resources) and the knife (the Financing Agreement) in the hands of the central, and district bureaucracies, and communities respectively can contribute to democratic decentralization. Three Social Action Funds (SAFs) in Africa are examined in this regard - in Malawi, Tanzania and Uganda. The Community Sub-project Cycle (CPSC), an integral part of the SAFs, is analyzed to show how a demand-driven process with in-built mutual accountability can result in communities realizing their aspirations while remaining accountable to government, and vice versa. The more formal way of capturing the issue would be to ask if governance can be broadened and deepened so that community needs become an intrinsic and measurable part of district and national plans. This"party line"on decentralization is that it is, in general, the way to go - all hindrances to it must be addressed and removed. The question that is very rarely asked is - how does this square with some of the Bank's other dominating approaches, such as Community-Driven Development ? This publication, based on experience from the field, outlines and responds to the challenges posed by this"dual"development. By putting some flesh on the bones of the"party line, "it provokes the intelligence without insulting it, and tells us that often, the real"poverty"is that of ideas and vision.

M. Jamshed, S. Khalique, Hiroki Suguri, Hafiz Farooq Ahmad · 5 authors

Grid is an ambitious and exciting global effort to develop an environment in which individual users can access computers, databases and experimental facilities simply and transparently, without having to consider where those faculties are located. Monitoring the behavior of the resources of a distributed system, especially grid, is necessary, both for determining the cause of performance problems, and for tuning the system, which results in optimized performance. However writing monitoring and management applications for grid resource is a complex task. This is due to the geographic distribution of resources and heterogeneous environments that are owned by different organizations. We have proposed architecture for autonomous grid node monitoring agent, to address the issues of complex resource monitoring and management. The architecture is based on grid monitoring architecture (GMA) and is autonomous as it provides functionality of equality, locality and self-containment, which are main components of autonomic controllability in any sub system as part of autonomous decentralized system (ADS) (K. Mori, 1993). The evaluation results of the proposed system proved the validity of the concept for achieving autonomous resource management in dynamic systems like grid

Yang Yi-xian

Most e-cash systems have anonymity to protect users' privacy, but few of them provide the non-repudiation service such that many problems such as blackmailing , money laundering , losing, misusing and double-spending can been avoided. Based on the partial blind digital signature and zero-knowledge proof,an e-cash system with non-repudiation is constructed in the article.

Mark Wynn, The Society of Christian Philosophers

In this collection of essays (old and new), Kai Nielsen offers a characteristically clear and forthright formulation of a perspective for which he is already well known.There is not much in the book that engages in detail with recent developments in analytic philosophy of religion; indeed, Nielsen comments that because of its habitual neglect of certain questions, philosophy of religion in this style fails to make any serious demand upon our attention: "I suppose we could analytically reconstruct and conceptually clarify Mary Baker Eddy's metaphysical tract too, but that would hardly enhance interest in it or further our understanding of the significance of religion.These analytical philosopher-theologians need first, against the antimetaphysical arguments of Wittgenstein, Davidson, Rorty, and Putnam, to give us some reason to think that there is in the sorts of things they are doing something significant" (p.20).A second, related difficulty for mainstream analytic philosophy of religion is that it is "very rationalistic"; rather than worrying about new versions of the traditional proofs, "what is crucial to face instead is whether we need a belief, however overwhelmed with intellectual impediments, in a Jewish, Christian or Islamic God to make sense of our lives and to live really human lives" (p.21).In these remarks, Nielsen sets two kinds of challenge for contemporary philosophical theology: to confront the difficulties inherent in any kind of metaphysical claim, and to consider whether religious commitment can be understood, and perhaps justified in some degree, by reference to its contribution to human flourishing.Let's take these challenges in tum.Nielsen evidently thinks it rather obvious that a metaphysically committed kind of religious belief is intellectually defective.Indeed, thinking in particular of the metaphysical dimension of religious belief, he comments: "I remain utterly flabbergasted that reflective, intelligent, and informed people ... can be believers" (p.393).Naturally Nielsen wonders whether his inability to understand the commitments of 'intelligent and informed' people raises a question about whether he has fully understood what is at stake here.Even so, the very obviousness of the case for atheism, from his point of view, seems at times to get in the way of a detailed presentation of

Chen Zu-ping

Through specific project example, elaborate the highway bridge of mountain area to dig hole stake base under the state that does not have water or few water, adopt underwater concrete the construction technical and control main points filled , project practice proof, under water or the state of losing water with underwater concrete, filling construction technology is a practical, economic and reasonable method.

Roger X. Lenard

The Indium Field Emission Thruster (In‐FET) is a highly characterized and space‐proven device based on space‐qualified liquid metal ion sources. There is also extensive experience with liquid metal ion sources for high‐brightness semiconductor fabrications and inspection Like gridded ion engines, In‐FETs efficiently accelerate ions through a series of high voltage electrodes. Instead of a plasma discharge to generate ions, which generates a mixture of singly and doubly charged ions as well as neutrals, indium metal is melted (157°C) and fed to the tip of a capillary tube where very high local electric fields perform more‐efficient field emission ionization, providing nearly 100% singly charged species. In‐FETs do not have the associated losses or lifetime concerns of a magnetically confined discharge and hollow cathode in ion thrusters. For In‐FETs, propellant efficiencies ∼100% stipulate single‐emitter currents ⩽10μA, perhaps as low as 5μA of current. This low emitter current results in ⩽0.5 W/emitter. Consequently, if the In‐FET is to be used for future Human and Robotic missions under President Bush’s Exploration plan, a mechanism to generate very high power levels is necessary. Efficient high‐power operation requires many emitter/extractor pairs. Conventional fabrication techniques allow 1–10 emitters in a single module, with pain‐staking precision required. Properly designed and fabricated In‐FETs possess electric‐to‐jet efficiency >90% and a specific mass <0.25 kg/kWe. MEMS techniques allow reliable batch processing with ∼160,000 emitters in a 10×10‐cm array. Developing a 1.5kW 10×10‐cm module is a necessary stepping‐stone for >500 kWe systems where groups of 9 or 16 modules, with a single PPU/feed system, form the building blocks for even higher‐power exploration systems. In 2003, SNL and ARCS produced a MEMS‐based In‐FET 5×5 emitter module with individually addressable emitter/extractor pairs on a 15×15mm wafer. The first MEMS thruster prototype has already been tested to demonstrate the proof‐of‐concept in laboratory‐scale testing. In this paper we discuss progress that has been achieved in the past year on fabricating silicon‐based MEMS In‐FETs.

Xiao Pu-yun

In this thesis,we design a protocol based on Zero-Knowledge Proof to realize the real time secure communication.This protocol is realized through the way of intertactive communication and is also an application of the Zero-Knowledge Proof in identification.The security of this protocol is based on the factorization of large numbers and RSA problems.This protocol can complete the identification with less amount of intetactive communication.

Mário Fortuna, José António Cabral Vieira, Margarida Mendes

One objective frequently found in models of decentralized financing is that of equalization. The concern is that poorer jurisdictions receive enough resources for basic services and for development promotion, thus eliminating horizontal and vertical imbalances. In Portugal, decentralization has occurred at two levels: the local, for the whole country and the regional for the autonomous regions of the Azores and Madeira. Decentralization to local governments has undergone several changes in recent decades. The current paper focuses on testing for the presence of an equalization effect in the models adopted to finance municipalities in Portugal, since the nineteen nineties. Using the theoretical background that maintains that for the presence of an equalizing effect it is necessary that, on a per capita basis, poorer regions or localities receive relatively more transfers than the richer jurisdictions, a test is made using a data set that includes all municipalities of Portugal. The situation of the two autonomous regions is controlled with dummy variables. The hypothesis that the models used have an equalizing effect is tested through the sign of the coefficient of the regression of per capita transfers on per capita own resources. In the presence of an equalizing effect the sign will be significant and negative. It is confirmed that, for the period under analysis, the municipalities with lower per capita own revenues are those that receive more transfers per capita. There is, therefore, an equalizing effect in the current transfer system to municipalities. Using pooled data, one can also conclude that the equalization effect has become stronger with the 1998 and 2002 reviews of the system, when compared to the system in effect in 1991.

Eduardo Rojas-Briales

Political principles for forest policy in the Mediterranean Region are analysed individually, considering their strengths and weaknesses, and are illustrated through encouraging examples and opportunities for development. The identified principles include: national sovereignty; decentralization; governance by contract; enforcement; capacity building; sustainable finance; minority protection (indigenous and local people); secure ownership rights (land tenure); equity; separation of powers; accountability; participation and partnership, transparency; iterative, audit and monitored; long-term commitment; holistic; consistency with international commitments; intersectoral coordination, consistency and synergies with other policies; integration with sustainable development policies; research and technology based; and conflict resolution.

Xiuyou Wang

On the base of home researching the idea of the proxy si gnature a kind of algorithm of the zero knowledge proof is proposed based on proxy signature in this paper. This algorithm has characteristics which are simple and easy to be realized.

Hong Zhu

In this paper, we give the definition of the bit commitment channel, implement its formulization, prove the implementation of the zero-knowledge proof with with it and introduce four schemes of implementing the bit commitment channel. It is suggested that zero-knowledge proof algorithm can bebased on bit commitment channel and an instance for this is given.

Rigobert C. Tossou, Moses Zinnah

The process of decentralisation and privatization of agricultural extension services in Benin must take into account important issues such as the news actors, including agricultural producer organisations, private sector and NGOs, the reduction in the power of high level extension administration, active participation or stakeholders in the financing of extension service, financial and technical assistance from the State, particularly for resource-limited communes, institutional changes that are adapted to both decentralisation context and local management capacity. In the new decentralised system, agricultural extension needs to be flexible and avoid hierarchical structures Most of the staff should be in the communes and should be oriented towards enhancing the capacity of farmers and the elected local governments to participate in the process of solving their problems and reach their development objectives, including financing of agricultural extension services. To achieve all this, adequate decisionmaking power and resources for extension activities should be transferred to commune level. The experience from Benin indicates the difficulties African countries in general, and Benin in particular, will face when trying to better tune extension activities to local needs.

Xiaobo Zhang

While, politically speaking, China has a centralized government structure with strong top-down mandates, under the country’s current fiscal system, local governments are responsible for providing most local public goods and services. Large differences in economic structures and revenue bases exist, however, causing the implicit tax rate and fiscal burdens in support of local government functions to vary significantly across jurisdictions. Regions initially endowed with a broader nonfarm tax base do not need to rely heavily on new and existing firms to finance public goods provision, which creates a healthy investment environment in support of nonfarm sector growth. In contrast, local governments in regions where agriculture is the major economic activity spend the majority of their resources on their own operating costs, leaving little for public investment. Because of the relatively high transaction costs associated with collecting taxes from the agricultural sector, local governments tend to levy the existing nonfarm sector heavily, thereby greatly inhibiting its growth. As a result, regional differences in economic structures and fiscal dependent burdens may translate into widening gaps in equality. Authors' Abstract