Theoretical computer science has found fertile ground in many areas of mathematics. The approach has been to consider classical problems through the prism of computational complexity, where the number of basic computational steps taken to solve a problem is the crucial qualitative parameter. This new approach has led to a sequence of advances, in setting and solving new mathematical challenges as well as in harnessing discrete mathematics to the task of solving real-world problems. In this talk, I will survey the development of modern cryptography -- the mathematics behind secret communications and protocols -- in this light. I will describe the complexity theoretic foundations underlying the cryptographic tasks of encryption, pseudo-randomness number generators and functions, zero knowledge interactive proofs, and multi-party secure protocols. I will attempt to highlight the paradigms and proof techniques which unify these foundations, and which have made their way into the mainstream of complexity theory.
In this tutorial, selected topics of cryptology and of computational complexity theory are presented. We give a brief overview of the history and the foundations of classical cryptography, and then move on to modern public-key cryptography. Particular attention is paid to cryptographic protocols and the problem of constructing key components of protocols such as one-way functions. A function is one-way if it is easy to compute, but hard to invert. We discuss the notion of one-way functions both in a cryptographic and in a complexity-theoretic setting. We also consider interactive proof systems and present some interesting zero-knowledge protocols. In a zero-knowledge protocol, one party can convince the other party of knowing some secret information without disclosing any bit of this information. Motivated by these protocols, we survey some complexity-theoretic results on interactive proof systems and related complexity classes.
September 11th was a pivotal day in American history. While only the fourth time in the history of the United States that foreign forces have invaded our territorial limits, it was the first time that substantial numbers of American civilians have been victims and remain under the cloud of realistic, recurring threat of further death and destruction. Osama bin Laden's terrorist network has warned of a "new storm of planes" (Associated Press, 11/14/2001) and he has directed his followers "to kill the Americans and plunder their money wherever and whenever they find it" (PBS' Frontline, 2/28/98). Indeed it is a threat of terror not unlike that faced by the British people at the hands of the Nazis during the Blitz where random, purposeless violence against the civilian population was also the intent. Unfortunately, our risks will not change soon, yet America will persevere and see victory: "Time and again, America has demonstrated a resilience that is rooted in the remarkable diversity of her people." ("Mongrel Nation," Smithsonian Magazine , November 2001, pp. 18-19.) In defeating this evil, tactical munitions and forces will play significant roles, but it is information that will be the single key to success for the United States. Indeed, information is the single most important factor in any comprehensive discussion of our war against terrorism. It is this proposition that defines the scope of this paper. We will consider information and information theory as our most effective war tool – as well as the legal and political authority for their covert use. Bombing alone, whether from cruise missiles, B-2 stealth bombers or venerable B52s, will not win a war. History is replete with examples where the most extensive bombing campaigns have not altered the resolve of the civilian population and have damaged but not destroyed the enemy war machine or the will of a population and its government to continue the fight. Similarly, ground forces, in the form of a punitive expedition, may bolster public and political morale but have minimal chances for quick success in either general or specific historical terms. Eighty years ago Britain, and the USSR more recently, learned that Afghanistan could not be conquered. Our own experience in Mexico in 1916 with a punitive expedition to punish a marauding Mexican revolutionary, involving ultimately over 10,000 cavalry forces, suggests the emotional and often illogical triggers for such events, the difficulty of retribution and the lack of certain success in such exercises. 1 Enterprise, 1799, 12-gun schooner, capturing a Tripolitan corsair in 1801; photograph of original art courtesy National Archives and Records Administration (NARA #19-N-12435). Thus in considering our potential course of action today, we should examine in some detail a striking historical analogue involving the use of traditional military forces against non-traditional enemies. Specifically, we will examine the first war fought by the United States against a foreign power – the Barbary Pirates – and the first raising of the Stars and Stripes in the Old War – at the taking of Tripoli. The details, factual parallels and lessons learned are significant, the primary lesson being the extreme difficulty as well as the time necessary to overcome decentralized threats. Who Were the Pirates?The pirates were individuals acting as a law unto themselves preying on the Western world for individual profit but in league with the temporal and religious rulers in Tripoli (the Bashaw), Algiers (the Dey) and Tunis (the Bey of Morocco) and more significantly, the supreme Sultan of the Ottoman Empire. The enemy? The enemy was Western civilization unless it would pay exorbitant tribute to their rulers. While in part a local "protection racket" intended to extort money from the then-superpowers, this contest also had substantial religious and state sponsorship elements. Although the Sultan's theocratic empire had become corrupt and weak and the local Barbary rulers were effectively autonomous in local affairs, the Sultan remained supreme and was the primary director and beneficiary of the piracy. The pirates, the local chieftains and the Empire were partners with the latter providing state authority, economic imperative and religious direction for the piracy. In effect, the Barbary pirates were in service to the grand Sultan fighting his continuation of the Crusades against Western interests. What Was the Cost of the Piracy? The contest began in 1785 when Algerian pirates seized two American ships and crews and it continued for years, especially after 1793. The patience of the United States began to end the next year (1794) with a Congressional authorization to build six ships of the line. But a peace, sometimes popular at any cost, was reached the next year (1795) with the Dey of Algeria. The terms required annual tribute of over $500,000 and the gift of a state-of-the-art 36-gun frigate. But appeasement seldom works, and, as a result of envy, the Bashaw demanded even greater payments and his own new American warship. Although U.S. reaction was delayed by the conflict with France, it was clear that the situation was intolerable, as evidenced by the 1799 letter from U.S. Counsel William Eaton to the Secretary of State in 1799 where he wrote that "... there is but one language which can be held to these people, and this is terror." And How Was the Piracy Brought to an End? By 1801 it was equally clear that the Bashaw had misjudged the new President Jefferson when he continued his demands, tore down the U.S. flag at the embassy and effectively declared war at that time. Jefferson promptly ordered the deployment of U.S. naval forces. Unfortunately, the 38-gun frigate Philadelphia ran aground outside the Tripoli harbor and was seized by the Bashaw's forces. Not one to surrender to the moment, the U.S. commander ordered a raiding party under Lt. Stephen Decatur into action, but without land forces, the United States could not take the city. Congress dithered and the problem continued. Four years later, the United States was forced to launch one of the first special operations. A U.S. Marine-led Arab army marched across 500 hundred miles of desert from Alexandria, Egypt, to Tripoli and seized the fort and palace of the Bashaw – thus giving rise to the commemorative line in the Marine Hymn "to the shores of Tripoli." But the United States was unable to install a permanent and more agreeable government there, and the troubles continued. Five years later, in 1810, the Algerians declared war on the United States and another naval expedition was launched, which attacked Algiers in 1815 and secured the release of American prisoners and the end of tribute there. The final resolution of this problem of international terrorism was not achieved until the world powers, acting in concert after the Napoleonic wars, ended piracy by force of arms, and the French captured and occupied Algiers in 1830. By that time this notable case of international terrorism – with state sponsorship, religious direction and substantial harm to U.S. commercial interests and civilians – had occupied America and its armed forces for some 45 years. It demonstrates further that short-term military successes may well not resolve intractable problems of this nature; rather it requires international commitment and a comprehensive destruction of the war-making capacity of the enemy. The present circumstances facing the United States are remarkably similar, yet even more intractable than the historical precedents. Against one prime enemy (the Taliban government of Afghanistan and Osama bin Laden), there are neither strategic infrastructure targets nor substantial government or military targets. Even the terrorist target hides in the shadows. 2 In sum, we do not have a contest between roughly symmetrical forces where we can effectively use the methods and mechanisms of historical military contests but an asymmetric war that requires new tools, foci and strategies. This we must not fear. Addressing change should not be considered traumatic or unique inasmuch as the necessity for military force changes and the prescience to recognize the needed change has been presented and successfully answered in the past and will be so today: "The methods and mechanisms of warfare have altered radically in recent times and they will alter still further in the future. But the United States is singularly fitted, by reason of the ingenuity of its people, the knowledge and skill of its scientists, the flexibility of its industrial structure, to excel in the arts of peace and to excel in the arts of war if that be necessary." – Vannevar Bush, president of the Carnegie Institution of Washington and President Roosevelt's Science Advisor, June 1940. The new tools for today's war? Information, information network theory and information technology. As senior representatives of the Department of Defense have said, "This is the most information-intensive war you can imagine. I think it is going to put us to the test in many ways. It is going to require a new mindset." The foci? The diplomatic, economic and financial theaters. The strategies? Many, but one critical one comes from the Information Age we live in – information network theory. That is, if we are fighting a dynamic, amorphous network we must look to information, information theory and information technology tools to aid us in our struggle. This approach translates into three discrete functional assignments: Understand the basic elements of an information network and the flow of information in that network. Ascertain the specifics of the network in question; and Use information network (i.e., organizational) theory to disrupt the network. Information networks consist of and can best be understood in terms of people (i.e., nodes) and the flow of information. The nodes can take one of three forms: Some are actors – people who do things and whose skill bases range from experts to clerical support. Others are the directors – people on the throne or subthrone and whose importance and role will range from titular to truly influential and motivating. And others are perhaps the most important, I call them gateways and they affect (and effect) the flow of information and activity; they are the key people in getting things done. These gateways, one might call them routers in information technology networks, take two forms. First, there are pure gateways, people who have the information or assets or know where to find them. These people have many relationships (i.e., links) both formal and informal; they may or may not have a position and de jure authority but they have de facto power. Second, there are gatekeepers, the people around the throne who control access to the throne and often manipulate the decisions of the throne. They often know (or assume) their importance, and their value is often their access rather than their knowledge or abilities. With respect to the operation of the network – the flow of information – there are three primary models in which the described nodes may be arranged. The first is a chain or hierarchical network where information moves – and must move – sequentially through a series of nodes; this is the old business model. The second is the star or hub network where a number of actor nodes are connected directly to a gateway or manager node and where information between actor nodes must go through that central node; this is typical of sophisticated criminal enterprises. The third is the multi-channel network where every node is connected to every other node; this model is collaborative in nature, quick acting and effective, but can be difficult to maintain given the high-level of communications required. It is the network of the information age and, when organized by terrorists, can be very effective (can launch multiple, repeated attacks from different points), very difficult to identify (is it acephalous or polycephalous?), and very difficult to destroy in its entirety (nodes are redundant). 3 Types of Networks Often, those in an organization do not think in terms of a network, do not understand the forms of a network and the flow of information, and do not characterize their personnel in terms of the previously described nodes. But it is critical to do so in business and war and there are now centers and tools for just such purposes. Today, we use this theory to help understand and better manage an organization especially in times of downsizing or in efforts to increase efficiency. It follows then that there is no reason why this theory might not be used to disrupt an organization; in other words, one might intentionally introduce internal conflicts or process inefficiencies in order to degrade organizational efficiency. With this approach, one does not need to arrest or kill every member of a terrorist organization; rather, one may target and remove key gateways or otherwise interfere with the flow of information and assets through the organization via key people. With this approach our task is significantly more finite and the work of replacement becomes a difficult and time-consuming task for the enemy; no longer can the terrorist organization survive simply by a ready flow of raw, often illiterate recruits from a disaffected population. How does one collect the necessary information about a highly secretive, insular organization in order to use this theory of disruption? In my judgment, the potential for direct recruitment of members of dedicated terrorist organizations is limited. Human collection in this is best directed with the of who have better knowledge and access than the United States will have – in other words, And the traditional tools and communications will continue to be of but of U.S. in the are their is, potential in the use of and technology. there can be attacks where a or (i.e., a does no and does no but rather, does a collection and a single discrete getting the from a used by a node in a terrorist network would be a to the network. about the to the by of the to a a technology tool that is in use in the business and with the against organized targets. to this key information about a specific network would be in the form of a where the would the of and between nodes. In such an even that could not be would in the of with such it becomes a of tools, to manage that in time and network and relationships that are not on the or are otherwise in a of that we understand the network, do we The is organizational theory to disrupt the and of the target information network. will often in the of organizational this and specific are not and others have about organizations by the of (i.e., and or by needed elements. Thus if one the information network – the organization – one may do many different things to the is one and The is to communications – the flow of information – and thus increase and efficiency. The first of approach is a form of that to the of the communications by The second is a form of that communications or otherwise the target from the use of the is to force the target to use some other form of perhaps perhaps effective, perhaps one that may be to or that may more information on of the first form of would be the of communications to terrorist nodes to identify of the second form of would be the of certain the network to use more through are more to may also be more to and, if may greater information as to the of the and especially terrorist extensive use of outside – While the for may from profit to it can end that money could end if the in that their line would be by and there are to such a the best and the nodes in an information network are not and do not at the Specifically, every organization has a of but people – often only to those on the It is not in our to the in a target organization; rather, we should to them and the and to the we can and thus maintain their to U.S. In effect, the becomes an we must identify the best and them to the organization to their an that on and in this The is that the world every member of a terrorist organization and we must our against the key the of the The of every organization is the people who it with and the we can destroy the of the we can the the people and thus the of destruction. This approach not only information about the United States but also information about the terrorist and its We can about their and them and to the where they from to to should be the range of covert to that could be the that the of the does not terror and that America has been a of from to to We can the of that America is a better than an who does not their language and only continued and war. In sum, put information in the hands of the people and the – after as the of our the of foreign and will know more about and have better access to information terrorist organizations in their this knowledge with their territorial authority and it follows that are there are political risks given the potential for different and but these must be against our the is a between and for the latter may rise to a government that the of But a of American covert action as well as foreign over the years that can permanent change that is in the of the people and the United States. In sum, of need not Western or in American foreign it is that they against terror and for the and in their And from history. with organizations – whether on or – have that can critical We can and must from our the about and very effective to and destroy organizations that a such would be to our own organizations that could and thus access to the enemy. The model for this approach is "The which was as the of and which to be an dedicated to and for the of In it by the in it was a for that had been by for the of to them and then their These are some of the that information and information theory may be effective war tools in this new and against this new enemy. these are in as and, in many will not or I that we must these new history has two things – that the United States has been to the war and that resolve is needed to win any war. The then becomes not so can we but rather political will and can we in this fight. We can find bin his people, his his his tools and his We can them we must have the political resolve to that it will be in terms of the of of our of the United States as a of and of our to some In the as to the legal and political especially when the use of information and theory is in a covert and may well the Congressional of when the and in the and against foreign under the and A was that the decisions such action were that it is difficult to be certain at was and As a was by President in in detail and that order does the and in recently, to Washington President has legal that the order does not his taking action against individual of as nodes in this under his authority and for the in those legal would be on the clear authority of a President to any at any with or without public This authority then the of which nodes and to the there is substantial for the approach – of the key gateway nodes such as of As for the problem is more the business of force is not one for which American are any such action would be by foreign or assets of foreign and with the and access to the targets in The for information presented by this war are Some will play key in the collection and of information – providing direct to the war on the or in Others will continue in and of new tools to in collection and And of us must as to the for the of our government in the force of I that this war should be neither an of nor an of rather it is a of no than that faced by a The of to a of war against and of is an that be to is a with the has been a member of the and most as the for the of information and as well as the of information and release he is on detail to the of where he as a with the of Information and the can be reached by at
TABLE OF CONTENTS INTRODUCTION I. SCOPE OF REVIEW A. The Art of Scope of Review B. The Administrative Procedure Act as a Guide C. Congressionally Defined Scope of Review Standards D. Unpredictability of Reversal Rates II. THE SUPREME COURT BELIEVES THESE WORDS MATTER A. Contrasting the Outcome Effect of Standards of Proof B. Standards of Proof and Scope of Review Compared C. Scope of Review in Other Settings III. SCOPE OF REVIEW IN CONTEXT: SOCIAL SECURITY DISABILITY, VETERANS DISABILITY, AND THE FREEDOM OF INFORMATION ACT A. Social Security Administration Disability Cases B. Veterans Disability Claims C. Freedom of Information Act Cases 1. The Special Case of Exemption 1 2. Judicial Views About Freedom of Information Act 3. Comparison to Reverse-Freedom of Information Act Cases D. Summary IV. JUDICIAL REVIEW OF SENTENCING DECISIONS V. LESSONS IN SCOPE OF REVIEW FOR THE SUPREME COURT AND CONGRESS A. Reassessing Social Security Administration Disability Review 1. The Supreme Court's Role: Tinkering with the Substantial Evidence Test 2. The Role of Congress: Changing the Structure of Review 3. Role of the Agency: Managing, Not Dictating, Outcomes B. Reassessing Freedom of Information Act Review 1. The Supreme Court's Role in Setting the Tone 2. Congressional Alternatives 3. Role of Agencies and the Department of Justice in Freedom of Information Act Review CONCLUSION APPENDIX A APPENDIX B Under existing standards, then, the courts may narrow their review to satisfy the demands for administrative discretion, and they may broaden it close to the point of substituting their judgment for that of the administrative agency. (1) After fifty years ... we have yet to agree on how this review should operate in practice. We are still struggling with where to draw the line between obsequious deference and intrusive scrutiny. (2) INTRODUCTION The purpose of calibrating the breadth--or scope--of judicial review over fact finding by administrative agencies is ultimately to allocate decision-making responsibility between the executive and judicial branches. Because Congress usually makes these decisions, all three branches have a stake in the process. In assigning oversight responsibilities, Congress makes a choice: it weighs the desire for efficient and timely agency action against the need to ensure consistent and fair decision making. In balancing these considerations, Congress intends factual support for agency decisions to be subject to varying levels of scrutiny or, on occasion, to be free from scrutiny. (3) Straightforward enough, one would think. Yet, as the introductory quotes suggest, after all these years, reviewing judges are still struggling to make sense of these standards, especially as they apply to scope of review of facts or of law and policy. (4) I. SCOPE OF REVIEW It is doubtful that Congress wants scope of review to be an irrelevant labeling exercise. Instead, one might reasonably expect that Congress wants outcomes, defined in terms of affirmances, remands, and reversals of agency actions, to vary according to the scope of review standard chosen (or at least to find some judicial recognition of these expectations). But it seems the question is rarely asked and its premise remains unexamined. To explore the relationship of to standards, this Article makes a preliminary attempt to measure against the relevant scope of review provisions. This outcomes analysis produces some intriguing correlations between results and formulas, along with some surprises that themselves serve to raise more questions. Although such an exercise can never produce total agreement about how scope of review standards should operate, it facilitates a better understanding of why Congress differentiates among these standards and why the lesson sometimes is lost on the courts. …
Two developments flowing from the institutional reforms in The Netherlands of the 1980s currently form ‘the usual suspects’ in a series of scandals or instances of public arousal within the public sector. The first factor is the large-scale decentralization of tasks from central government to provincial and municipal authorities. Initiated under the name of democratization and efficiency this decentralization programme was part of a large package of operations, including deconcentration, deregulation, privatization, and reconsideration, that were to to slim down central government in terms of personnel, tasks and organization. Second, managerialism, i.e. the adoption of business management ideas and concepts by public administrators, entered Dutch public service vocabulary during the second half of the 1980s. Managerialism did not limit itself only to central government agencies but also — and perhaps more succinctly — found openings in provincial and municipal authorities, mainly as a fierce reaction against the ‘bureaucratism’ of daily administrative practice to counter the relative deprivation perceived by civil servants in relation to their private sector counterparts. This article shows that the decentralization of financial management and the emergence of ‘reinvention’ ideas have had autonomous but drastic effects. While the former blinded central government and provincial controllers, the latter legitimized practices that even under a private sector regime would have been deemed improbable.
The study reviews the strategy for a prospective health development, and the health benefits associated with decentralization, in a likely challenging near to medium term period in Indonesia. It addresses the major government reorganization, expected to take effect in January 2001, which could well define the social process during the next decade, consisting of decentralization of spending authority, enhanced access to resources at local government levels, and civil service reform. The potential health system benefits, associated with decentralization, will enable citizens to become involved systematically in decisions regarding health policy, design, and financing, as well as influencing service provision. The report describes the health system performance, and costs in the country, namely an adaptation of health for all, aimed at a wide coverage, featuring integrated service provision at the primary health level. However, mixed results proved great imbalances, for low income families lagged behind other quintiles in terms of infant mortality rates, prevalence of specific diseases, and nutrition problems, while households in the top expenditure distribution, proved high uses of public facilities, compared to the bottom expenditure distribution. The pre-crisis policy is examined, i.e., the impacts on the provider-client equation; and, policy options offer opportunities through decentralization, reform related issues, and effective partnerships with non-governmental organizations, and donors.
The introduction of user-payment for health services is frequently followed by concern about the impact on equity of access for poor people. Decentralizing governments often try to remedy the created inequities by putting in place safety nets in the form of exemptions and waivers in the user-fee systems. However, where user payments merely operate as local government strategies for health financing, without national policy they are likely to be self-defeating, as local governments are frequently more interested in raising revenue to meet recurrent costs of devolved services than in promoting equity. Thus guidelines put in place by the central government to operationalize safety nets are seen by local governments as being contradictory to this goal, and are thus ignored or altered to suit the district revenue aims. This study was carried out to investigate the context and the constraints in implementing exemption schemes. Data were collected in two selected administrative districts of Uganda (Mbarara and Mukono). Qualitative approaches to data collection were adopted, namely focus group discussions and key informant interviews with policy-makers, health administrators, service providers and community members. These methods were combined with document review. We found little evidence of safety-net guidelines initiated by decentralized/local governments, since district local governments had little motivation to extend exemptions, waivers or credits. The conclusion is that safety nets such as waivers and exemptions will only be effective if they are backed by a national health financing policy, they reconcile the often competing demands of local government revenue needs, and are strictly enforced and supervised by both the local and central governments. The implications of the findings for remedying the tension between the needs for cost recovery and for attainment of equity goals through exemption policies for the poor and indigent are discussed.
Zero-knowledge interactive proof is a useful tool for designing identification and digital signature schemes. We propose a new interactive proof based identification and signature scheme.
FlexiInternational develops and maintains FlexiFinancials, a suite of object-oriented, client/server software products for accounting. These interacting applications support general ledger, accounts payable and receivable, purchasing, fixed assets, order processing, inventory maintenance, and workflow functions. This paper describes a distributed component, transaction-based architecture that comprises the foundation for future development.
Although ABS has been widely spread on the commercial market for twenty years, throughgoing investigations with rigorous theoretical background have been lacking in the automotive literature. The control strategies of commercial ABS are mostly based on table rules to be calibrated through various experiments and tests, and the system dynamics cannot be effectively considered in the controller design. Due to the challenges in the automobile industry it is desired to develop a technique which still enhances the control performance and robustness with respect to various vehicle types and environment conditions. Motivated by these goals, a robust adaptive control algorithm is developed in this work. The proof of asymptotic stability is based on the Lyapunov method. The objective of such control is to maximize the tire friction under the assumption of knowing the optimal value of target slip. It is shown that, without any prior knowledge of the tire force and system parameters, the slip error is bound to converge to zero asymptotically. The robustness of the control system with respect to variation of the system parameters is guaranteed. The brake dynamic system to be controlled includes mechanical motion equations and the hydraulic circuit equations. A two-level control scheme is applied for the controller design, which considers the both parts separately.
We describe efficient constructions for various cryptographic primitives in private-key as well as public-key cryptography. Our main results are two new constructions of pseudo-random functions. We prove the pseudo-randomness of one construction under the assumption that factoring (Blum integers) is hard while the other construction is pseudo-random if the decisional version of the Diffie--Hellman assumption holds. Computing the value of our functions at any given point involves two subset products. This is much more efficient than previous proposals. Furthermore, these functions have the advantage of being in TC 0 (the class of functions computable by constant depth circuits consisting of a polynomial number of threshold gates). This fact has several interesting applications. The simple algebraic structure of the functions implies additional features such as a zero-knowledge proof for statements of the form " y = f s ( x )" and " y ≠ f s ( x )" given a commitment to a key s of a pseudo-random function f s .
Some of the salient biology is reviewed, so that it can be seen how suitable the immune system is as a prototype of "bottom up" artificial intelligence. It is stressed that the immune system is entirely distributed (to first approximation). Its agents, the cells, are highly complex. Much is known about these cells and their interaction with each other and with pathogens, and the system is of high biological and medical interest. Major questions to be addressed include the following: 1) what are the "goals" of the immune system, and how can feedback promote these goals? 2) how can spatial organization allow non-specific chemical signals to select specific immune elements that contribute effectively to system goals? 3) how and in what sense can immune system performance be improved in the absence of an overall goal? and 4) how does the immune system compare with other autonomous decentralized systems.
We present a complete promise problem for SZK, the class of languages possessing statistical zero-knowledge proofs (against an honest verifier). The problem is to decide whether two efficiently samplable distributions are either statistically close or far apart. This characterizes SZK with no reference to interaction or zero-knowledge. From this theorem and its proof we are able to establish several other results about SZK, knowledge complexity, and efficiently samplable distributions.
Energy management systems/supervisory control and data acquisition (EMS/SCADA) systems are usually geographically distributed and have operational organizations. They are changing in accordance with the various and varying environments, and they should be flexible enough to adapt to those changes quickly. The paper proposes a new architecture called SCOPE (System Configuration of Power Control System) to realize flexible and reliable EMS/SCADA systems. SCOPE makes application programs independent of the operational organization and system configuration of the EMS/SCADA system, i.e., application programs are not influenced by changes in them. These properties make EMS/SCADA systems flexible and reliable, and also the development of EMS/SCADA systems becomes efficient and economical. Through developing and evaluating a SCOPE prototype system, it has been confirmed that the flexibility and maintainability of EMS/SCADA systems based on the SCOPE architecture has been improved.
The basic principles of the intelligent home technology are presented and it is described how it can be modeled as a multi-agent system. Because of the complexity of the system it is argued that it should be generated by an evolutionary process and maintained according to the principles of the immune system.
Sung Jun Park, Tae‐Hoon Kim, Dong Ho Won, Young Hwa An
We propose a new notion of an entrusted undeniable signature which is a variant of the undeniable signature. Also we propose a provably entrusted undeniable signature whose security can be proved. The proposed entrusted undeniable signature is a new type of undeniable signature in which the signer confirms his(her) signature to any verifier without the help of court but the verifier can't run the disavowal protocol in the undeniable signature which only court can run to solve the dispute later. The proposed scheme is constructed by a combination of the undeniable signature and zero-knowledge interactive proof system. The proposed provably entrusted undeniable signature is much the same as our entrusted undeniable signature but using the public key residue cryptosystem, which is polynomially secure, for the commitment scheme.
We consider which aspects of the two prover model are necessary for their striking language recognition and zero-knowledge capabilities. We approach this question by looking at an alternative, more symmetric model which we call the double verifier model. We find that in this model the shared randomness of the verifiers is key to the language recognition power: if the verifiers don't share randomness the power is PSPACE; otherwise it is MIP=NEXPTIME. We find that the shared randomness of the provers is necessary for zero-knowledge: if the provers don't share randomness, statistical zero-knowledge is only possible for languages in BPP/sup NP/; else it is possible for all of NEXPTIME. These results have immediate implications for the standard two-prover model. We see that correlations between the verifier's queries is crucial for the language recognition power of two prover proofs. In particular, the natural analog of IP=AM does not hold in the two-prover model unless NEXPTIME=PSPACE. Similarly, we see that shared randomness, or correlation of the provers answers, is necessary for the statistical zero-knowledge of two prover proofs.>
A new framework is proposed for the analysis of communication protocols that require accountability, such as those for electronic commerce. Informal arguments are presented to show that a heretofore un-explored property "provability" is pertinent to examine the potential use of communication protocols in the context of litigation, and in the context of audit. A set of postulates which are applicable to the analysis of proofs in general (e.g., zero knowledge proofs), and the proofs of accountability in particular, are proposed. The proposed approach is more natural for the analysis of accountability then the existing belief logics that have been used in the past for the analysis of key distribution protocols. Some recently proposed protocols for electronic commerce and public-key delegation are analyzed to illustrate the use of the new analysis framework in detecting (and suggesting remedies for eliminating) their lack of accountability, and in detecting and eliminating redundancies.>
We suggest a systematic way to design secure password-based authentication protocols, which is the password verifier model. The method makes use of zero-knowledge interactive proof (ZKIP), which has been known not to be useful for the protection of passwords. For the proper usage of ZKIP, we introduce a specialized form of ZKIP, which has a secret coin tossing stage.
Concerns use of spacecraft as autonomous coordinated teams. Generalized reasoning capability offered by advanced distributed software technology and AI can cope with unexpected events and uncertainty, and so close the loop of perception, decision and eventually deliberation. The team members play interchangeable roles and negotiate about the task. We present a multi-agent system to provide a high degree of autonomy and support for coordination among team members. We use JPL formation flying mission initial architectures as benchmark. Our target is to avoid inconsistencies/disagreements between two or more participants in a collaborative context, increase the system's fault tolerance in cases such as loss of a member while the system still operates reliably. We address cooperation between collaborating independent autonomous agents. In a top-down organization agents are coordinated hierarchically, where the agents at the top of the hierarchy make the majority of the intelligent group decisions. In a more structured but still hierarchical organization, lower-level agents exercise more intelligence. A lower-level agent can advance a plan for the others to follow, and a higher-rank agent decides on the best plans. Although more rigid, the centralized intelligence organization allows for less communication among agents, so is more straightforward to implement. The decentralized approach requires more communication, but the intelligence is truly distributed, which makes for a more flexible, adaptive and efficient organization.
The problem of suppressing zero-input limit cycles in coupled-form state-space digital filters when the quantization is performed after the multiplication is addressed. To the extent of the authors' knowledge, no proof has been presented that the parasitic oscillations are suppressed for poles anywhere in the unit circle, under that condition. Some authors have addressed this subject, but their results constrain the poles to a bounded region inside the unit circle. With the objective of exploring this topic further, the authors present a proof that for poles whose angle is either 0, /spl plusmn/45, /spl plusmn/90, /spl plusmn/135 or 180 degrees and whose radius is lower than one, the second-order state-space coupled-form digital filter is free of zero-input limit cycles when quantizers placed just after the multipliers implement magnitude truncation.
This paper proposes a new proof-based approach to safe evolution of distributed software systems. Specifically it extends the simple certification mechanism of proof-carrying code (PCC) to make it interactive and probabilistic, thereby devising code with interactive proof (CIP). With CIP, a code consumer is convinced, with overwhelming probability, of the existence and validity of a safety proof of a transmitted code through interaction with a code producer. The class of safety properties that are provable by CIP is larger than the class provable by PCC, provided that each code consumer is allowed to spend a reasonable amount of time on verification. Moreover, CIP can be further extended to devise code with zero-knowledge interactive proof (CZKIP). This concept is useful, for example, when the code producer wants to use the safety proof as a kind of "copyright" of the code.
A zap is a 2‐round, public coin witness‐indistinguishable protocol in which the first round, consisting of a message from the verifier to the prover, can be fixed “once and for all” and applied to any instance. We present a zap for every language in NP, based on the existence of noninteractive zero‐knowledge proofs in the shared random string model. The zap is in the standard model and hence requires no common guaranteed random string. We present several applications for zaps, including 3‐round concurrent zero‐knowledge and 2‐round concurrent deniable authentication, in the timing model of Dwork, Naor, and Sahai [J. ACM, 51 (2004), pp. 851–898], using moderately hard functions. We also characterize the existence of zaps in terms of a primitive called verifiable pseudorandom bit generators.
We consider the problem of designing an efficient oblivious transfer (OT) protocol that is provably secure in a concurrent setting, i.e., where many OT sessions may be running concurrently with their messages interleaved arbitrarily. Known OT protocols use zero-knowledge proofs, and no concurrent zero-knowledge proofs are known that use less than a poly-logarithmic number of rounds (at least without requiring a pre-processing phase, a public random string, an auxiliary string, timing constraints, or pre-distributed public keys). We introduce a model for proving security of concurrent OT protocols, and present a protocol that is proven secure in this model based on the decisional Diffie-Hellman problem. The protocol is efficient, requiring only a slightly non-constant number of rounds.