Public Inputs Research Articles

Pyecsca: Reverse engineering black-box elliptic curve cryptography via side-channel analysis

Side-channel attacks on elliptic curve cryptography (ECC) often assume a white-box attacker who has detailed knowledge of the implementation choices taken by the target implementation. Due to the complex and layered nature of ECC, there are many choices that a developer makes to obtain a functional and interoperable implementation. These include the curve model, coordinate system, addition formulas, and the scalar multiplier, or lower-level details such as the finite-field multiplication algorithm. This creates a gap between the attack requirements and a real-world attacker that often only has black-box access to the target – i.e., has no access to the source code nor knowledge of specific implementation choices made. Yet, when the gap is closed, even real-world implementations of ECC succumb to side-channel attacks, as evidenced by attacks such as TPM-Fail, Minerva, the Side Journey to Titan, or TPMScan [MSE+20; JSS+20; RLM+21; SDB+24].We study this gap by first analyzing open-source ECC libraries for insight into realworld implementation choices. We then examine the space of all ECC implementations combinatorially. Finally, we present a set of novel methods for automated reverse engineering of black-box ECC implementations and release a documented and usable open-source toolkit for side-channel analysis of ECC called pyecsca.Our methods turn attacks around: instead of attempting to recover the private key, they attempt to recover the implementation configuration given control over the private and public inputs. We evaluate them on two simulation levels and study the effect of noise on their performance. Our methods are able to 1) reverse-engineer the scalar multiplication algorithm completely and 2) infer significant information about the coordinate system and addition formulas used in a target implementation. Furthermore, they can bypass coordinate and curve randomization countermeasures.

Power and positionality in the practice of health system responsiveness at sub-national level: insights from the Kenyan coast

BackgroundHealth system responsiveness to public priorities and needs is a broad, multi-faceted and complex health system goal thought to be important in promoting inclusivity and reducing system inequity in participation. Power dynamics underlie the complexity of responsiveness but are rarely considered. This paper presents an analysis of various manifestations of power within the responsiveness practices of Health Facility Committees (HFCs) and Sub-county Health Management Teams (SCHMTs) operating at the subnational level in Kenya. Kenyan policy documents identify responsiveness as an important policy goal.MethodsOur analysis draws on qualitative data (35 interviews with health managers and local politicians, four focus group discussions with HFC members, observations of SCHMT meetings, and document review) from a study conducted at the Kenyan Coast. We applied a combination of two power frameworks to interpret our findings: Gaventa’s power cube and Long’s actor interface analysis.ResultsWe observed a weakly responsive health system in which system-wide and equity in responsiveness were frequently undermined by varied forms and practices of power. The public were commonly dominated in their interactions with other health system actors: invisible and hidden power interacted to limit their sharing of feedback; while the visible power of organisational hierarchy constrained HFCs’ and SCHMTs’ capacity both to support public feedback mechanisms and to respond to concerns raised. These power practices were underpinned by positional power relationships, personal characteristics, and world views. Nonetheless, HFCs, SCHMTs and the public creatively exercised some power to influence responsiveness, for example through collaborations with political actors. However, most resulting responses were unsustainable, and sometimes undermined equity as politicians sought unfair advantage for their constituents.ConclusionOur findings illuminate the structures and mechanisms that contribute to weak health system responsiveness even in contexts where it is prioritised in policy documents. Supporting inclusion and participation of the public in feedback mechanisms can strengthen receipt of public feedback; however, measures to enhance public agency to participate are also needed. In addition, an organisational environment and culture that empowers health managers to respond to public inputs is required.

Political uncertainty and revenue sharing in international contracting

This study investigates a critical source of political uncertainty for foreign investors in a centralised political system: leadership turnover within local governments. Our stylised model suggests that risk-averse foreign investors, faced with this uncertainty, tend to offer a larger revenue share to their local partners in international joint ventures (IJVs). This incentivises local officials to provide the necessary authorisations and public inputs for IJVs. Using a unique Chinese dataset that links city-level leadership changes with firm-level incentive structures, our empirical analysis provides robust evidence supporting this framework.

Efficiency and Welfare Effects of Fiscal Policy in Emerging Economies: The Case of Morocco

This paper studies the welfare cost of fiscal policy in developing economies where a significant fraction of the population is government spending-dependent, using as an example Morocco. We develop a Dynamic General Equilibrium model representing an economy populated by three types of households: Standard Ricardian households with access to the financial market, households who supply labor but have no access to the financial market, and non-active government-dependent households (who behave as hand-to-mouth agents). The paper computes welfare changes of different tax rates and alternative spending policies and quantifies the trade-off of fiscal policy across the different groups of agents. We find that: (i) Distortions from some taxes can be positive due to the presence of public inputs; (ii) Output efficiency can be gained by changing the tax mix while keeping constant fiscal revenues; and (iii) Social welfare gains can be obtained by increasing public investment and reducing government consumption and keeping lump-sum transfers constant.

Follow the leader? The long‐run interaction between public and private sector wage growth in the UK

AbstractWith one‐fifth of the UK labour force employed in the public sector, public sector pay and its interaction with private sector pay is an important driver of the macroeconomy. Using new data on sector‐level earnings and sector–industry‐level pay settlements, this paper addresses the fundamental question of which sector leads and which follows in terms of earnings determination. We find that in the long run, public sector wages adjust to wages set in the private sector, maintaining a consistent relationship. We further find that there can be significant wage spillovers from the public sector to the private sector in the short run. These tend to be more pronounced for private sector industries that are domestically facing, characterized by low worker bargaining power, or reliant on public sector inputs. This paper's findings have important implications for macroeconomic policy that aims to balance inflationary forces and fiscal funding pressures.

A machine learning application to Google Maps Reviews as a participatory planning tool

ABSTRACT Public participation is vital to achieving successful plan outcomes, whereas meaningful participation requires at least informing and consulting the public. However, collecting frequent feedback from the public is a labour-intensive process. Information technologies like Google Maps Reviews offer to collect extensive public inputs by allowing users to share their feedback and ratings about services. Machine learning methods are ideal for analyzing these reviews to understand users’ experiences. This study proposes a machine learning application using Google Maps Reviews to examine feedback on the selected parks in Istanbul, Türkiye. Reviews provide insights into not only park features but also its social structure. The introduced method supports surveys and interview methods preferred by planners.

Greek Public Sector’s Efficient Resource Allocation: Key Findings and Policy Management

The public sector has limited resources, and how these resources are allocated in expenditures and investments is crucial. Our article focuses on controlling this allocation for the Greek economy from 2000 to 2021, which includes the country’s debt crisis. To do so, we utilized data from national accounts, categorized inputs and outputs, and examined their volatility and stability over time using statistical and mathematical methods. Our analysis revealed that the crisis impacted the size and allocation of public inputs and outputs. While some sectors of the Greek economy displayed stability in financing over time, others were more volatile. Using a mathematical accounting approach contributes to the academic discourse on rational resource allocation in the public sector. Our results validate the tax hypothesis for primary revenues and expenditures and advocate that it is necessary to make targeted recruitments in the sector that is needed each time while keeping the total number constant, which leads to the need to redistribute public sector workers. In the same way, public projects should not only focus on infrastructure projects but should also be spread to new areas related to climate change and the agricultural sector.

Aggregate and distributional effects of school closure mitigation policies: Public versus private education

We use a human capital formation model to compare extending school time to private education subsidies in mitigating the adverse effects of school closures. The impact on inequality and mobility depends crucially on the substitutability between private and public inputs.

5.I. Round table: Governing private sector engagement: opportunities & challenges in public health policy & practice

Abstract Health systems all over the world rely on a mix of public and private inputs in the financing and provision of health services and products, with varying degrees of involvement of the private sector. The importance of private sector engagement was evident during the COVID-19 pandemic, when governments had to work with the private sector to meet the demand of health services and products. Private actors were engaged or worked in partnership with the public health system to supply rapid and often innovative solutions to strengthen some existing services and develop new ones. In tandem, various governance challenges such as the lack of transparency, inefficiencies, and potential corruption - undermining effective health system performance were also experienced. This workshop aims to shed light on the learnings from private sector engagement (both positive and negative) during the pandemic, discuss the relevant issues shaping the governance of private sector engagement in public health, and the policy and practice implications in the post-pandemic world. Session plan: Opening/welcome by Dr Natasha Azzopardi Muscat Director, Division of Health Systems and Public Policy, WHO Regional Office for Europe (5 mins) - Tentative Brief reflection on the Importance of governing private sector engagement - opportunities and challenges in public health policy and practice by Gabriele Pastorino Technical Officer, WHO Regional Office for Europe (5 mins) Technical overview: key messages from the joint WHO EURO/European Observatory policy brief on lessons learnt from private sector engagement during COVID-19 by Anna Maresso, European Observatory on Health Systems and Policies (5 mins) - Tentative Roundtable discussion with panelists on key learnings on private sector engagement during COVID-19. (40 minutes) Panelist representing Policy, Academia, and Practice would be engaged in a roundtable discussion, answering questions to shed more light on this topic. This would be followed by interactive Q& A with the audience. Proposed questions: -what we have learned from the COVID-19 pandemic on engaging with the private sector (common challenges and opportunities) -examples of successful engagements and innovative collaborations that were maintained after the pandemic or scaled up relevant issues shaping the governance of private sector engagement in public health, and the policy and practice implications in the post-pandemic world. Key take-home messages from the session by Dr Naomi Limaro Nathan, Consultant, WHO Regional Office for Europe. (5 mins) Closing remarks Key learning outcomes: • To enable an increased awareness of the opportunities and challenges of governing private sector engagement in public health policy and practice in the post-pandemic world. •To build momentum for public health stakeholders to engage in the discourse and contribute to strengthening the governance of private sector engagement. Key messages • The pandemic experience has provided an opportunity for learnings - both good and bad to enable strengthened governance for private sector engagement. • Engaging with the private sector in a post-pandemic world is vital to addressing health system needs and achieving UHC.

TUTORING EFFICACY, HOUSEHOLD SUBSTITUTION, AND STUDENT ACHIEVEMENT: EXPERIMENTAL EVIDENCE FROM AN AFTER‐SCHOOL TUTORING PROGRAM IN RURAL CHINA

AbstractAfter‐school tutoring has risen globally despite limited evidence of effectiveness. We implement a randomized after‐school tutoring program in rural China where many children are left‐behind by parents in care of grandparents. Compared to tutees cared for by parents, those in care of grandparents reported much smaller home‐tutoring reductions but larger test‐score gains. We interpret our data analysis with a model with tutoring efficacy and substitution between private and public inputs both differing by family background: Increased public tutoring generates larger test‐score gains for children who experience greater tutoring efficacy and lesser substitution with household inputs, consistent with our estimates.

Vertical fiscal externality in public education inputs: When federal and state governments have different time perspectives

This study investigates how equilibrium under a unitary nation can be achieved through fiscal transfer from (to) the federal government to (from) the state government when both levels of government supply public education to immobile residents under a simple endogenous growth framework fueled by human capital accumulation. We introduce the different time perspectives of both levels of government as a key consideration. Although both levels of government are interested in both the utility level of the present generation and the growth rate that can be attained by accumulating human capital through education, they place different weight on the value of these objectives. We first show that the federal government can replicate the equilibrium outcome that can be achieved under a unitary nation by implementing fiscal transfer between the different levels of government. Second, if the federal government places a large weight on the growth rate, or has a more long-run perspective than the state government, the federal tax rate becomes positive. Third, as the federal government has a stronger long-run perspective, fiscal transfer from the federal government to the state government increases.

Optimal tax enforcement with productive public inputs

We study optimal public expenditure and tax enforcement in a simple one-sector, dynamic endogenous growth model where agents optimize consumption and evasion; evasion is costly, while public expenditure increases private capital productivity. We show that tax evasion costs and the efficiency of endogenous audits play a crucial role in determining the relationship between tax evasion, tax rates, public expenditure, and growth. The key elements to improve tax enforcement are efficiency in the audit process and increased productivity in public expenditure. Increasing tax evasion costs could reduce tax evasion, but when tax enforcement is inefficient, this might trigger a perverse effect in which a tax rate increase reduces tax revenue. This finding implies that government spending depends on the efficiency of the audit process: expanding government expenditure optimally or increasing private productivity is impossible without improvements in tax compliance.

Side-channel Elimination via Partial Control-flow Linearization

Partial control-flow linearization is a code transformation conceived to maximize work performed in vectorized programs. In this article, we find a new service for it. We show that partial control-flow linearization protects programs against timing attacks. This transformation is sound: Given an instance of its public inputs, the partially linearized program always runs the same sequence of instructions, regardless of secret inputs. Incidentally, if the original program is publicly safe, then accesses to the data cache will be data oblivious in the transformed code. The transformation is optimal: Every branch that depends on some secret data is linearized; no branch that depends on only public data is linearized. Therefore, the transformation preserves loops that depend exclusively on public information. If every branch that leaves a loop depends on secret data, then the transformed program will not terminate. Our transformation extends previous work in non-trivial ways. It handles C constructs such as “goto,” “break,” “switch,” and “continue,” which are absent in the FaCT domain-specific language (2018). Like Constantine (2021), our transformation ensures operation invariance but without requiring profiling information. Additionally, in contrast to SC-Eliminator (2018) and Lif (2021), it handles programs containing loops whose trip count is not known at compilation time.

Cost analysis of an intrapartum quality improvement package for improving preterm survival and reinforcing best practices in Kenya and Uganda.

Preterm birth is a leading cause of under-5 mortality, with the greatest burden in lower-resource settings. Strategies to improve preterm survival have been tested, but strategy costs are less understood. We estimate costs of a highly effective Preterm Birth Initiative (PTBi) intrapartum intervention package (data strengthening, WHO Safe Childbirth Checklist, simulation and team training, quality improvement collaboratives) and active control (data strengthening, Safe Childbirth Checklist). In our analysis, we estimated costs incremental to current cost of intrapartum care (in 2020 $US) for the PTBi intervention package and active control in Kenya and Uganda. We costed the intervention package and control in two scenarios: 1) non-research implementation costs as observed in the PTBi study (Scenario 1, mix of public and private inputs), and 2) hypothetical costs for a model of implementation into Ministry of Health programming (Scenario 2, mostly public inputs). Using a healthcare system perspective, we employed micro-costing of personnel, supplies, physical space, and travel, including 3 sequential phases: program planning/adaptation (9 months); high-intensity implementation (15 months); lower-intensity maintenance (annual). One-way sensitivity analyses explored the effects of uncertainty in Scenario 2. Scenario 1 PTBi package total costs were $1.11M in Kenya ($48.13/birth) and $0.74M in Uganda ($17.19/birtth). Scenario 2 total costs were $0.86M in Kenya ($23.91/birth) and $0.28M in Uganda ($5.47/birth); annual maintenance phase costs per birth were $16.36 in Kenya and $3.47 in Uganda. In each scenario and country, personnel made up at least 72% of total PTBi package costs. Total Scenario 2 costs in Uganda were consistently one-third those of Kenya, largely driven by differences in facility delivery volume and personnel salaries. If taken up and implemented, the PTBi package has the potential to save preterm lives, with potential steady-state (maintenance) costs that would be roughly 5-15% of total per-birth healthcare costs in Uganda and Kenya.

The Efficiency of Rural Public Finance Inputs in Promoting Rural Revitalization: Empirical Analysis Based on Henan Province, China

<p>The No.1 document of the Central Government of China has been on the theme of "agriculture, rural areas and farmers" for nearly ten years, placing the solution of "agriculture, rural areas and farmers" at the forefront of the Chinese government's work. Located in the Central Plains, Henan Province in China is one of the major agricultural provinces in China and plays an extremely important role in the field of agricultural production in China. This paper uses an empirical approach and the DEA-Malquist model to study the efficiency of rural public financial inputs to rural revitalisation in Henan Province. The results show that due to different levels of regional economic development, the efficiency of rural public finance investment in Henan Province in promoting rural revitalisation varies, and there is a phenomenon of unreasonable allocation of funds. At the same time, the region's agricultural base also has a greater impact on the efficiency of financial investment. Therefore, Henan Province should adjust measures according to the different regional economic levels and agricultural bases to improve the efficiency of the use of fiscal funds.</p>

Watermains Leakage and Outdoor Water Use Are Responsible for Significant Phosphorus Fluxes to the Environment Across the United States

AbstractHuman activity has led to excess phosphorus (P) concentrations and the continued eutrophication of coastal and freshwaters across the United States (US). Developing more effective P management policy requires a comprehensive understanding of P sources in the environment. Public water systems across the United States widely dose water with phosphate (PO4) in order to control the corrosion of lead and copper within their distribution networks. Using public water system PO4 dosing facility data and target PO4‐P dosing concentrations, we estimate that PO4 dosing added 4–14.9 kt PO4‐P yr−1 into the US water distribution network in 2015. Using estimates of public water supply inputs and domestic water deliveries, we estimate that 0.7–2.6, and 0.8–3.1 kt PO4‐P yr−1 were then lost from the network due to watermains leakage and outdoor water use, respectively. After accounting for these fluxes, we estimate that 9.3 kt PO4‐P yr−1 was then returned to wastewater treatment plants (WWTPs) and accounted for up to 2.7% of the national WWTP influent P load. As sources of P to the environment, lower and upper estimates of combined watermains leakage and outdoor water use PO4‐P fluxes exceeded P loads to surface waterbodies from documented point sources across 461–541 counties. The exceedance of these fluxes above other major components of the US P‐budget emphasizes the need to include them in P source apportionment studies, both across the US and in other countries where public water supplies are dosed with PO4.

Productive effects of public spending, spillovers, and optimal matching grant rates

This study uses the model in which a central government gives a subsidy to the jurisdictions, and analyzes the optimal matching grant rate for local public spending that has characteristics of both public goods and public inputs. If the expenditures are public inputs, they raise the productivity of the jurisdiction which provides them. Their spillover effects to other regions are assumed to influence consumption and/or production. Contrary to this approach, traditional analyses of matching grants for public spending have only focused on public goods and consumption spillover. By considering these factors, this study obtains some intriguing results. The productive effect of public inputs on the optimal matching grant rate depends on whether the degree of the production spillover is higher than that of the consumption spillover.

Federalism and primary-income inequality

ABSTRACT The paper studies the effects of federalism on primary-income (before taxes and transfers) inequality. A jurisdiction in a federal system chooses an economic policy for the interests of the jurisdiction, but the policy is determined uniformly at the national level in a unitary system. A jurisdiction with more resources can choose a higher level of public inputs such as productivity-enhancing investment and hence attract more businesses in a federal system, but a jurisdiction in a unitary system cannot. More business activities result in higher incomes, and income inequality is higher in a federal system than in a unitary system. The paper also provides an empirical analysis, and available evidence suggests that primary-income inequality is higher in a federal system.

Environmental Regulation Modeled as a Public Input Proportional to Capital Investment

Abstract Public inputs, when referred to as unpaid factors, are included in production specifications characterized by constant returns to scale in all inputs. In equilibrium, the public input rent generated by this configuration must be allocated among firms based on some measure of productive activity. Herein, decentralized environmental regulation is modeled as a public input of the unpaid type. Environmental rent is then rationed to private firms in proportion to their capital investment. Results reveal that source based capital taxation will capture these environmental rents, however, will not yield efficiency in the devolved interjurisdictional framework. The capital tax must be complemented by benefit taxation in order to provide efficient local public expenditures and socially optimal levels of environmental quality. JEL classification numbers: H42, H54, H71. Keywords: Environmental federalism, Capital tax, Public inputs, Efficiency.

Public Input Provision, Tax Base Mobility, and External Ownership

This article investigates the distortionary impacts of tax base mobility and external ownership on public input provision. Regional governments compete for mobile tax bases (e.g., business capital). The impact of regional public policy partially accrues to non-residents because immobile factors (e.g., business land) are subject to external ownership. This article derives an optimal rule for regional public input provision that illustrates how these two distortionary impacts depend on the nature of production functions. The impact of external ownership is particularly complex. To explore this impact in detail, the case of production functions with constant elasticity of substitution is examined. Public inputs with different productivity impacts yield fairly different implications of external ownership for inefficient public input provision.