3,494 research outputs found
Accountability for Misbehavior in Threshold Decryption via Threshold Traitor Tracing
A -out-of- threshold decryption system assigns key shares to parties so that any of them can decrypt a well-formed ciphertext. Existing threshold decryption systems are not secure when these parties are rational actors: an adversary can offer to pay the parties for their key shares. The problem is that a quorum of parties, working together, can sell the adversary a decryption key that reveals nothing about the identity of the traitor parties. This provides a risk-free profit for the parties since there is no accountability for their misbehavior --- the information they sell to the adversary reveals nothing about their identity. This behavior can result in a complete break in many applications of threshold decryption, such as encrypted mempools, private voting, and sealed-bid auctions.
In this work we show how to add accountability to threshold decryption systems to deter this type of risk-free misbehavior. Suppose a quorum of or more parties construct a decoder algorithm that takes as input a ciphertext and outputs the corresponding plaintext or . They sell to the adversary. Our threshold decryption systems are equipped with a tracing algorithm that can trace to members of the quorum that created it. The tracing algorithm is only given blackbox access to and will identify some members of the misbehaving quorum. The parties can then be held accountable, which may discourage them from selling the decoder in the first place.
Our starting point is standard (non-threshold) traitor tracing, where parties each holds a secret key. Every party can decrypt a well-formed ciphertext on its own. However, if a subset of parties collude to create a pirate decoder that can decrypt well-formed ciphertexts, then it is possible to trace to at least one member of using only blackbox access to the decoder . Traitor tracing received much attention over the years and multiple schemes have been developed.
In this work we develop the theory of traitor tracing for threshold decryption, where now only a subset of or more parties can collude to create a pirate decoder . This problem has recently become quite important due to the real-world deployment of threshold decryption in encrypted mempools, as we explain in the paper. While there are several non-threshold traitor tracing schemes that we can leverage, adapting these constructions to the threshold decryption settings requires new cryptographic techniques. We present a number of constructions for traitor tracing for threshold decryption, and note that much work remains to explore the large design space
LIPIcs, Volume 251, ITCS 2023, Complete Volume
LIPIcs, Volume 251, ITCS 2023, Complete Volum
Spectrum auctions: designing markets to benefit the public, industry and the economy
Access to the radio spectrum is vital for modern digital communication. It is an essential component for smartphone capabilities, the Cloud, the Internet of Things, autonomous vehicles, and multiple other new technologies. Governments use spectrum auctions to decide which companies should use what parts of the radio spectrum. Successful auctions can fuel rapid innovation in products and services, unlock substantial economic benefits, build comparative advantage across all regions, and create billions of dollars of government revenues. Poor auction strategies can leave bandwidth unsold and delay innovation, sell national assets to firms too cheaply, or create uncompetitive markets with high mobile prices and patchy coverage that stifles economic growth. Corporate bidders regularly complain that auctions raise their costs, while government critics argue that insufficient revenues are raised. The cross-national record shows many examples of both highly successful auctions and miserable failures. Drawing on experience from the UK and other countries, senior regulator Geoffrey Myers explains how to optimise the regulatory design of auctions, from initial planning to final implementation. Spectrum Auctions offers unrivalled expertise for regulators and economists engaged in practical auction design or company executives planning bidding strategies. For applied economists, teachers, and advanced students this book provides unrivalled insights in market design and public management. Providing clear analytical frameworks, case studies of auctions, and stage-by-stage advice, it is essential reading for anyone interested in designing public-interested and successful spectrum auctions
Autobidders with Budget and ROI Constraints: Efficiency, Regret, and Pacing Dynamics
We study a game between autobidding algorithms that compete in an online
advertising platform. Each autobidder is tasked with maximizing its
advertiser's total value over multiple rounds of a repeated auction, subject to
budget and/or return-on-investment constraints. We propose a gradient-based
learning algorithm that is guaranteed to satisfy all constraints and achieves
vanishing individual regret. Our algorithm uses only bandit feedback and can be
used with the first- or second-price auction, as well as with any
"intermediate" auction format. Our main result is that when these autobidders
play against each other, the resulting expected liquid welfare over all rounds
is at least half of the expected optimal liquid welfare achieved by any
allocation. This holds whether or not the bidding dynamics converges to an
equilibrium and regardless of the correlation structure between advertiser
valuations
Improving the SEP licensing framework by revising SSOs’ IPR policies
This thesis examines the SEP licensing framework with a view to understanding whether it can be improved by revising IPR policies.
The ICT standardisation, which provides interoperability, is one of the building blocks of the modern economy. Put simply, without standards, there would not be IoT or for example, consumers would only be able to connect to a wireless network with devices specifically built for that network. Standards are not a new phenomenon; however, they became more complex with the increasing importance of technology, which made them, in return, more dependent on patented technologies (i.e. SEPs). SEPs cause complications in standardisation as they require SEP owners and potential licensees to negotiate/agree on usually complex licensing agreements. Although SSOs have attempted to regulate this relationship with their IPR policies, now it seems these policies cannot keep up with the changing dynamics and needs in standardisation. Dysfunctions in the system do not only affect competition in the relevant markets, they also prejudice consumers’ interests, for example, by passing on higher prices to cover supra-competitive royalties.
In particular, since the first Rambus case in the US, competition/antitrust agencies and courts have been dealing with SEP-related issues. Recently, the EU has been considering addressing some of those with legislation. Conversely, this research derives from the notion that active standardisation participants are better equipped to deal with SEP-related issues, and flexible IPR policies are more suitable for addressing these issues in the dynamic standardisation ecosystem.
Against this backdrop, this comparative research aims to identify areas where SEP licensing framework can be improved by reforming IPR policies, and it develops some proposals using the black-letter and empirical research methods that SSOs can implement
Threshold Encrypted Mempools: Limitations and Considerations
Encrypted mempools are a class of solutions aimed at preventing or reducing
negative externalities of MEV extraction using cryptographic privacy. Mempool
encryption aims to hide information related to pending transactions until a
block including the transactions is committed, targeting the prevention of
frontrunning and similar behaviour. Among the various methods of encryption,
threshold schemes are particularly interesting for the design of MEV mitigation
mechanisms, as their distributed nature and minimal hardware requirements
harmonize with a broader goal of decentralization.
This work looks beyond the formal and technical cryptographic aspects of
threshold encryption schemes to focus on the market and incentive implications
of implementing encrypted mempools as MEV mitigation techniques. In particular,
this paper argues that the deployment of such protocols without proper
consideration and understanding of market impact invites several undesired
outcomes, with the ultimate goal of stimulating further analysis of this class
of solutions outside of pure cryptograhic considerations. Included in the paper
is an overview of a series of problems, various candidate solutions in the form
of mempool encryption techniques with a focus on threshold encryption,
potential drawbacks to these solutions, and Osmosis as a case study. The paper
targets a broad audience and remains agnostic to blockchain design where
possible while drawing from mostly financial examples
The theory of wasting assets with reference to the regulation and pricing of gold in the South African gold mining industry
The main aim of this thesis is to present and critically analyse the theory of wasting assets with regard to extractive mineral industries in general and to the pricing and regulation of gold . ii'" particular. Furthermore, to consider the contention that the. price of minerals {such as gold) has been "too low11 in the current generation and that market forces have· led to a 11 too rapid11 depletion of these · resources. The argument that H is the government's duty to intervene and extend the lives of the mines is· also queried •. A detailed examination of the South African· gold mining taxation formula attempts to show how this type of· government intervention (in the for in of .a sliding scale taxation formula) results in uneconomic act ions by mine owners and non-optimal extraction patterns of the resource The contention is put forward that, given certain considerations, market ibrces should lead to the most optimal use of an exhaustible resource where property rights exist and are def inable0 Unlike common property resources, such as the fisheries, where market .forces fail to make the most optimal use of the resource, government intervention is unjustified The scope of the paper is intended to cover both the underlying theory of wasting assets and to relate this theory to gold in part icu1 ar., The determinants of the gold price will be considered as well as the effects of government intervention via· the gold mining taxation formula on the South· African gold mining industry. Hence, the thesis is divided into two sections: "Theoretical 11 and "Gold and Gold Mining". With regard to the method of paper - Literature. from as far back ,· as 1931 regarding .the theory of wasting assets, was collected and .analysed. The information for the section on 11 Gold and Gold Mining" was collected from the various organisations involved in the industry, notably the Chamber of Mines _and the Mineral Engineering Department . . 9f the University of the Witwatersrand. Information regarding the Gold Mining Taxation and Lease Formulae was obtained from the various Government Reports that have been printed since the introduction of the Mining Taxation. Act No. 6 in 191
Maximizing Miner Revenue in Transaction Fee Mechanism Design
Transaction fee mechanism design is a new decentralized mechanism design problem where users bid for space on the blockchain. Several recent works showed that the transaction fee mechanism design fundamentally departs from classical mechanism design. They then systematically explored the mathematical landscape of this new decentralized mechanism design problem in two settings: in the plain setting where no cryptography is employed, and in a cryptography-assisted setting where the rules of the mechanism are enforced by a multi-party computation protocol. Unfortunately, in both settings, prior works showed that if we want the mechanism to incentivize honest behavior for both users as well as miners (possibly colluding with users), then the miner revenue has to be zero. Although adopting a relaxed, approximate notion of incentive compatibility gets around this zero miner-revenue limitation, the scaling of the miner revenue is nonetheless poor.
In this paper, we show that if we make a mildly stronger reasonable-world assumption than prior works, we can circumvent the known limitations on miner revenue, and design auctions that generate optimal miner revenue. We also systematically explore the mathematical landscape of transaction fee mechanism design under the new reasonable-world and demonstrate how such assumptions can alter the feasibility and infeasibility landscape
Learning in Repeated Multi-Unit Pay-As-Bid Auctions
Motivated by Carbon Emissions Trading Schemes, Treasury Auctions, and
Procurement Auctions, which all involve the auctioning of homogeneous multiple
units, we consider the problem of learning how to bid in repeated multi-unit
pay-as-bid auctions. In each of these auctions, a large number of (identical)
items are to be allocated to the largest submitted bids, where the price of
each of the winning bids is equal to the bid itself. The problem of learning
how to bid in pay-as-bid auctions is challenging due to the combinatorial
nature of the action space. We overcome this challenge by focusing on the
offline setting, where the bidder optimizes their vector of bids while only
having access to the past submitted bids by other bidders. We show that the
optimal solution to the offline problem can be obtained using a polynomial time
dynamic programming (DP) scheme. We leverage the structure of the DP scheme to
design online learning algorithms with polynomial time and space complexity
under full information and bandit feedback settings. We achieve an upper bound
on regret of and respectively, where is the number of units demanded by the
bidder, is the total number of auctions, and is the size of
the discretized bid space. We accompany these results with a regret lower
bound, which match the linear dependency in . Our numerical results suggest
that when all agents behave according to our proposed no regret learning
algorithms, the resulting market dynamics mainly converge to a welfare
maximizing equilibrium where bidders submit uniform bids. Lastly, our
experiments demonstrate that the pay-as-bid auction consistently generates
significantly higher revenue compared to its popular alternative, the uniform
price auction.Comment: 51 pages, 12 Figure
Current issues of the management of socio-economic systems in terms of globalization challenges
The authors of the scientific monograph have come to the conclusion that the management of socio-economic systems in the terms of global challenges requires the use of mechanisms to ensure security, optimise the use of resource potential, increase competitiveness, and provide state support to economic entities. Basic research focuses on assessment of economic entities in the terms of global challenges, analysis of the financial system, migration flows, logistics and product exports, territorial development. The research results have been implemented in the different decision-making models in the context of global challenges, strategic planning, financial and food security, education management, information technology and innovation. The results of the study can be used in the developing of directions, programmes and strategies for sustainable development of economic entities and regions, increasing the competitiveness of products and services, decision-making at the level of ministries and agencies that regulate the processes of managing socio-economic systems. The results can also be used by students and young scientists in the educational process and conducting scientific research on the management of socio-economic systems in the terms of global challenges
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