Dynamic consent management allows a data subject to dynamically govern her consent to access her data. Clearly, security and privacy guarantees are vital for the adoption of dynamic consent management systems. In particular, specific data protection guarantees can be required to comply with rules and laws (e.g., the General Data Protection Regulation (GDPR)). Since the primary instantiation of the dynamic consent management systems in the existing literature is towards developing sustainable e-healthcare services, in this paper, we study data protection issues in dynamic consent management systems, identifying crucial security and privacy properties and discussing severe limitations of systems described in the state of the art. We have presented the precise definitions of security and privacy properties that are essential to confirm the robustness of the dynamic consent management systems against diverse adversaries. Finally, under those precise formal definitions of security and privacy, we have proposed the implications of state-of-the-art tools and technologies such as differential privacy, blockchain technologies, zero-knowledge proofs, and cryptographic procedures that can be used to build dynamic consent management systems that are secure and private by design.
By making a state of the art on the regulations and standards, in force and in progress, this deliverable aims to better inform the regulatory aspects of the design of reusable packaging and to analyse the barriers and opportunities to implement the reuse of packaging, so as to spot potential conflicts with constraints linked to this purpose. The first part is dedicated to the main definitions useful to understand the subject of packaging reuse. To make a relevant state of the art in the second part, we investigated two major issues which both concern the reuse of packaging, at European and national levels, in countries of BUDDIE-PACK's partners: hygiene on one hand and packaging on the other hand, in order to identify any pain point in the reuse of packaging. It can be noted that all the hygiene regulations that we have identified relate to the food sector and do not include any mention of non-food products, such as home care products, which are operated in the use case of ASEVI. Regulation (EC) N°852/2004 lays down the general rules on the hygiene of foodstuffs and especially requires that containers used for transporting foodstuffs to be designed so that adequate cleaning is possible, and to be dedicated for the transport of foodstuffs. Complementary good practices are also mentioned in the Codex Alimentarius, an internationally recognized collection of food standards, and in the ISO 22000 and EN 15593:2008 standards. In Directive 98/83/EC on the quality of water likely to be used in the food industry, despite microbiological and chemical requirements, a vagueness can be observed on three parameters impacting hygiene, which are the colour of water, its smell and its taste: indeed, the Directive only requires that these parameters must be “acceptable to consumer” and that “no unnatural change” can be observed, which means that non-compliance thresholds may vary according to the stakeholders. Standard EN 17735:2022 is essential to guarantee the safety of washing, as it specifies the hygiene requirements for the operation of commercial dishwashers in a professional environment and also includes the main guidelines for obtaining hygienic results for treated articles. To close the chapter on hygiene, one must note that a standard exists to assess the efficience of disinfectants in the food area through a quantitative test on a nonporous surface, such as steel, but that such a standard does not exist on plastic surfaces. The third part presents the packaging regulations from four angles (design, food contact, production and recycling, non-food products) and an institutional analysis. Directive 94/62/EC, on Packaging and Packaging Waste (PPW), is currently being revised by the European Commission: it should become a Regulation, directly applicable by all Member States, and shall further support the implementation of reusable packaging. The vote is expected in September 2023. It should be noticed that the restrictions set in Directive (EU) 2019/904 SUP (Single-Use Plastic) only concern single-use plastic packaging. Regulation (EU) N°10/2011 regulates the safety of plastic materials in contact with food. It gives guidance on specific migration test methods, including for reusable materials: its limitation is that it considers a low number of reuses, so it does not take into account the possible degradation of the material, such as scratches which are inherent in the prolonged reuse of packaging and which can impact the migrations of substances. The REACH Regulation, also under review, establishes procedures for evaluating information on the properties and hazards of chemical substances. Due to the many substances used in the manufacture of plastics and required to make them sustainable, REACH revision may have an impact on the development of reusable packaging. In Regulation (EU) 2022/1616 setting the operating rules of all recycling stages, it is interesting to remember that recycling schemes, of any material, in a closed and controlled chain may be considered as suitable to recycle waste plastic into food-contact plastic, in the same way as mechanical PET recycling. This principle could be implemented for any reusable packaging provided that it is used in a closed system and that external non-foodstuffs contaminations are avoided. Regulation (EC) N°648/2004 on detergents, such as ASEVI’s products, does not mention any requirement on the packaging. Some of BUDDIE-PACK's partners countries, France, Spain, Germany and The Netherlands, have passed laws to implement reusable packaging, with a focus on food or beverage consumption, on-site or on-the-go. While France explicitly banned single-use packaging in several sectors in addition to the on-site catering, Germany and The Netherlands set less restrictive incentives for on-site and take-away catering, and Spain addressed quantified reuse targets for take-away beverage and beverage sold in food retail stores. Note that the UK's exit from the EU led to the transposition of most of regulations mentioned in this deliverable into national law, without significant differences with European regulations, except the SUP Directive, for which an equivalent legislation is expected in October 2023. Beyond these regulations already adopted to promote the reuse of packaging, this dynamic is much broader than Europe: thus, the United Nations Environment Assembly has created an Intergovernmental Negotiating Committee responsible for drafting a text "legally binding" by October 2024. The work sessions should result in a first draft text by November 2023. The suggestions of NGOs converge on the development of shared logistics infrastructures and user-friendly packaging, the expansion of DRS to encourage consumer engagement, but also the standardisation of LCA methods to ensure data reliability. The NGO Zero Waste Europe also insists on the need to implement economic levers to encourage companies to offer reusable packaging, and consumers to choose it. The fourth part gives more details on the main expected modifications in the regulations being revised, especially the PPW and the REACH Regulations, which could impact the development of reusable packaging. To help provide answers to BUDDIE-PACK use cases, the fifth part summarises the regulations and standards that cover each use case, in order to find all information sources at a glance, to incorporate them into the packaging design and to produce packaging fully adapted to the needs. To conclude with this deliverable, the sixth part explains the main barriers and above all the opportunities, at regulatory, technical, safety, social and economic levels. As the hygiene regulations establish an obligation of results towards the actors of the value chain, and not of means, the reuse of packaging does not conflict with hygiene constraints on condition that each part provides the required health guarantees on its scope. Our innovation approach and its proof of concept should allow to identify risky points in advance and to develop solutions to scale up without risk. The debate on the revision of the REACH Regulation will have to be considered into the SSbD concept. In addition, discussions on the PPW Regulation and the Global Plastic Pollution Treaty may open new perspectives of strategies to implement reusable packaging by the end of 2024. The two major technical obstacles are the lack of knowledge about the ageing of plastics through cycles of use and washing (degradation of polymer chains after heat treatment, repeated sealing or mechanical stress, water abrasion) and logistics (collection of used packaging, storage, transport). The Digital Product Passport should therefore be an effective lever for optimising the return of packaging and its durability. Moreover, the standardisation of packaging, coordinated at a European level in cooperation with EPRs and business operators shall allow an optimisation of transport and storage. Capitalising on the experience of manufacturing and retailing sectors which already reuse their packaging will be decisive, especially on the logistics. Solving safety obstacles will be also essential to develop the reuse of packaging, i.e. defining compliance criteria on rinsing and drying to ensure there is no residue of detergent or water, and investigating the risks of migration of substances and release of microplastics, from a material which has been used multiple times. On the first point, depending on the sector, industrial means allow to prevent food contamination (ventilation, humidity control, ease to clean premises and equipments, specially trained staff, etc.). Capitalising on the experience of actors already involved is also an important action lever, such as bottlers or school catering. Social barriers are difficult to solve because they require changing deep-rooted habits, for both packaging’s users and consumers. Restaurants may be afraid of wasting time in their daily tasks (additional time to handle, store, wash, wipe, etc.). Some of consumers could be reluctant to use a packaging that they gauge it has already been used (scratch, small stain, discoloration, etc.), even if it is clean and safe, which requires a specific pedagogy. Active consumerism can effectively contribute to the proper functioning of the reuse loop and is very rewarding for the consumer, as we see it with the successful development in Europe of DRS. Giving back an economic value to packaging should also prevent waste from being abandoned. Even if their exact role is not yet defined, business operators will have to be strongly involved in the management of the reuse loop in opposition to the management of waste, which is dealt by local authorities. This involvement and the initial investment in packaging will impact their business model. To help them, public policies should support adequate eco-modulations and the development of shared logistics. Various incentives should be also addressed to consumers to encourage them to ch
Nada Amin, John C. Burnham, François Garillot, Rosario Gennaro · 7 authors
We introduce Lurk, a new LISP-based programming language for zk-SNARKs. Traditional approaches to programming over zero-knowledge proofs require compiling the desired computation into a flat circuit, imposing serious constraints on the size and complexity of computations that can be achieved in practice. Lurk programs are instead provided as data to the universal Lurk interpreter circuit, allowing the resulting language to be Turing-complete without compromising the size of the resulting proof artifacts. Our work describes the design and theory behind Lurk, along with detailing how its implementation of content addressing can be used to sidestep many of the usual concerns of programming zero-knowledge proofs.
Jim Woodcock, Mikkel Schmidt Andersen, Diego F. Aranha, Stefan Hallerstede · 11 authors
This report describes the state of the art in verifiable computation. The problem being solved is the following: The Verifiable Computation Problem (Verifiable Computing Problem) Suppose we have two computing agents. The first agent is the verifier, and the second agent is the prover. The verifier wants the prover to perform a computation. The verifier sends a description of the computation to the prover. Once the prover has completed the task, the prover returns the output to the verifier. The output will contain proof. The verifier can use this proof to check if the prover computed the output correctly. The check is not required to verify the algorithm used in the computation. Instead, it is a check that the prover computed the output using the computation specified by the verifier. The effort required for the check should be much less than that required to perform the computation. This state-of-the-art report surveys 128 papers from the literature comprising more than 4,000 pages. Other papers and books were surveyed but were omitted. The papers surveyed were overwhelmingly mathematical. We have summarised the major concepts that form the foundations for verifiable computation. The report contains two main sections. The first, larger section covers the theoretical foundations for probabilistically checkable and zero-knowledge proofs. The second section contains a description of the current practice in verifiable computation. Two further reports will cover (i) military applications of verifiable computation and (ii) a collection of technical demonstrators. The first of these is intended to be read by those who want to know what applications are enabled by the current state of the art in verifiable computation. The second is for those who want to see practical tools and conduct experiments themselves.
Blockchain has become a popular decentralized paradigm for various applications in the zero-trust environment. The core of the blockchain is the consensus protocol, which establishes consensus among all the participants. PoW (Proof-of-Work) is one of the most popular consensus protocols. However, the PoW consensus protocol which incentives the participants to use their computing power to solve a meaningless hash puzzle is continuously questioned as energy-wasting. To address these issues, we propose an efficient and secure consensus protocol based on proof of useful federated learning for blockchain (called FedChain). We first propose a secure and robust blockchain architecture that takes federated learning tasks as proof of work. Then a pool aggregation mechanism is integrated to improve the efficiency of the FedChain architecture. To protect model parameter privacy for each participant within a mining pool, a secret sharing-based ring-all reduce architecture is designed. We also introduce a data distribution-based federated learning model optimization algorithm to improve the model performance of FedChain. At last, a zero-knowledge proof-based federated learning model verification is introduced to preserve the privacy of federated learning participants while proving the model performance of federated learning participants. Our approach has been tested and validated through extensive experiments, demonstrating its performance.
Blockchains are decentralized and immutable databases that are shared among the nodes of the network. Although blockchains have attracted a great scale of attention in the recent years by disrupting the traditional financial systems, the transaction privacy is still a challenging issue that needs to be addressed and analysed. We propose a Private Token Transfer System (PTTS) for the Ethereum public blockchain in the first part of this paper. For the proposed framework, zero-knowledge based protocol has been designed using Zokrates and integrated into our private token smart contract. With the help of web user interface designed, the end users can interact with the smart contract without any third-party setup. In the second part of the paper, we provide security and privacy analysis including the replay attack and the balance range privacy attack which has been modelled as a network flow problem. It is shown that in case some balance ranges are deliberately leaked out to particular organizations or adversial entities, it is possible to extract meaningful information about the user balances by employing minimum cost flow network algorithms that have polynomial complexity. The experimental study reports the Ethereum gas consumption and proof generation times for the proposed framework. It also reports network solution times and goodness rates for a subset of addresses under the balance range privacy attack with respect to number of addresses, number of transactions and ratio of leaked transfer transaction amounts.
Open access
3 source records
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
The privacy-preserving data aggregation is a critical problem for many applications where multiple parties need to collaborate with each other privately to arrive at certain results. Blockchain, as a database shared across the network, provides an underlying platform on which such aggregations can be carried out with a decentralized manner. Therefore, in this paper, we have proposed a scalable privacy-preserving data aggregation protocol for summation on the Ethereum blockchain by integrating several cryptographic primitives including commitment scheme, asymmetric encryption and zero-knowledge proof along with the hypercube network topology. The protocol consists of four stages as contract deployment, user registration, private submission and proof verification. The analysis of the protocol is made with respect to two main perspectives as security and scalability including computational, communicational and storage overheads. In the paper, the zero-knowledge proof, smart contract and web user interface models for the protocol are provided. We have performed an experimental study in order to identify the required gas costs per individual and per system. The general formulation is provided to characterize the changes in gas costs for the increasing number of users. The zero-knowledge proof generation and verification times are also measured.
With the increasing presence of blockchain-based distributed applications in various aspects of daily life, there has been a growing focus on the privacy protection of blockchain ledgers and the corresponding regulatory technologies. However, current mainstream solutions primarily concentrate on the verifiable encryption of blockchain transaction addresses and contents, neglecting the regulatory requirements for private transactions. Moreover, the few monitorable solutions suffer from issues such as excessive centralization and a single-minded approach to regulatory content. To address these deficiencies, this paper proposes a blockchain privacy-preserving scheme that supports multi-level regulation through the utilization of zero-knowledge proofs (zk-SNARKs) and attribute-based encryption (ABE). Firstly, by leveraging zk-SNARKs, this scheme achieves blockchain privacy-preserving within an account model, enabling the concealment of user transaction addresses and values. Secondly, by employing attribute-based encryption, a multi-level regulatory model is developed alongside the privacy protection measures, allowing for selective disclosure of transaction content. Finally, we analyze the security of the proposed scheme and compare it with other schemes, discussing its advantages in terms of privacy, security, and regulatory capabilities, we also provide a preliminary evaluation of the scheme's efficiency through experiments. In conclusion, the scheme demonstrates strong privacy by relying on mathematical proofs through zk-SNARKs to ensure security while comprehensively safeguarding content. It also achieves multi-level regulation on the foundation of privacy protection, with comprehensive regulatory coverage and decentralized regulatory authority.
With the increasing interest for advanced protocols for Multi Party Computation, Fully-Homomorphic Encryption or Zero Knowledge proofs, a need for cryptographic algorithms with new constraints has emerged. These algorithms, called Arithmetization-Oriented ciphers, seek to minimize the number of field multiplications in large finite fields F2n or Fp. Among them, Ciminion is an encryption algorithm proposed by Dobraunig et al. in Eurocrypt 2021. In this paper, we show a new univariate modelization on a variant of Ciminion proposed by the designers. This instance restricts the attacker to at most 2 s/2 data, where s is the security level. Because the designers chose to reduce the number of rounds in that specific attacker model, we are able to attack the cipher for large security levels. We also propose some slight modifications of Ciminion that would overcome this vulnerability.
Abstract: This research paper surveys the landscape of cryptography, encompassing historical origins and modern applications. Beginning with foundational concepts, it explores encryption, decryption, ciphers, and keys, spanning symmetric and asymmetric cryptography. Historical context unfolds, tracing cryptography from ancient Egyptian hieroglyphs to Julius Caesar's cipher. The study then transitions to contemporary subjects. Elliptic Curves and Cryptography are investigated, showcasing their significance in secure communication, demonstrating ECC key exchange and AES-GCM encryption using python and Comparative analysis of ECC, RSA, and Diffie-Hellman sheds light on their performance. Zero-Knowledge Proofs are introduced as tools for privacy-preserving verification followed by an exploration of various Zero-Knowledge Proof (ZKP) protocols. By presenting practical implementation examples using Python, the paper illustrates how these proofs can be applied in real-world scenarios. Random Number Generation is examined and distinction between pseudorandom number generators (PRNGs) and cryptographically secure PRNGs (CSPRNGs) is emphasized conducting a thorough comparative analysis of PRNGs and CSPRNGs, considering factors like correlation, independence, periodicity, and entropy. Furthermore, the section evaluates the performance of different random number generation techniques. Fully Homomorphic Encryption emerges as a groundbreaking concept, discussing its mathematical properties, practical implementation, parameter selection, and optimization techniques enabling computation on encrypted data. Cryptographic Secret Sharing Schemes are explored for secure information distribution. The paper concludes by delving into the Chinese Remainder Theorem's applications within modern cryptographic protocols, particularly in RSA decryption and the integration factorization process of the RSA public key cryptosystem. It also provides a comprehensive overview of the theoretical foundations of primality testing, a pivotal aspect of the RSA algorithm. Overall, this research paper provides a comprehensive exploration of cryptography's historical context, core concepts, advanced techniques, and practical implementations, offering valuable insights into the realm of secure communication
With the development of deep learning, the demand for similarity matching between texts in text classification is becoming increasingly high. How to match texts quickly under the premise of keeping private information secure has become a research hotspot. However, most existing protocols currently have full set limitations, and the applicability of these methods is limited when the data size is large and scattered. Therefore, this paper applies the secure vector calculation method for text similarity matching in the case of data without any complete set constraints, and it designs a secure computation protocol of text similarity (SCTS) based on the semi-honest model. At the same time, elliptic-curve cryptography technology is used to greatly improve the execution efficiency of the protocol. In addition, we also analyzed the possibility of the malicious behavior of participants in the semi-honest-model protocol, and further designed an SCTS protocol suitable for the malicious model using the cut-and-choose and zero-knowledge-proof methods. By proposing a security mechanism, this protocol aims to provide a reliable and secure computing solution that can effectively prevent malicious attacks and interference. Finally, through the analysis of the efficiencies of the existing protocols, the efficiencies of the protocols under the malicious model are further verified, and the practical value for text classification in deep learning is demonstrated.
Open access
Cryptography and Data Security
Privacy-Preserving Technologies in Data
Advanced Steganography and Watermarking Techniques
Yathin Kethepalli, Rony Joseph, Sai Raja Vajrala, Jashwanth Vemula · 5 authors
Crypto-wallets or digital asset wallets are a crucial aspect of managing cryptocurrencies and other digital assets such as NFTs. However, these wallets are not immune to security threats, particularly from the growing risk of quantum computing. The use of traditional public-key cryptography systems in digital asset wallets makes them vulnerable to attacks from quantum computers, which may increase in the future. Moreover, current digital wallets require users to keep track of seed-phrases, which can be challenging and lead to additional security risks. To overcome these challenges, a new algorithm is proposed that uses post-quantum cryptography (PQC) and zero-knowledge proof (ZKP) to enhance the security of digital asset wallets. The research focuses on the use of the Lattice-based Threshold Secret Sharing Scheme (LTSSS), Kyber Algorithm for key generation and ZKP for wallet unlocking, providing a more secure and user-friendly alternative to seed-phrase, brain and multi-sig protocol wallets. This algorithm also includes several innovative security features such as recovery of wallets in case of downtime of the server, and the ability to rekey the private key associated with a specific username-password combination, offering improved security and usability. The incorporation of PQC and ZKP provides a robust and comprehensive framework for securing digital assets in the present and future. This research aims to address the security challenges faced by digital asset wallets and proposes practical solutions to ensure their safety in the era of quantum computing.
Open access
2 source records
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Abstract This note is just a modest contribution to prove several classical results in Combinatorics from notions of Duality in some Artinian K -algebras (mainly through the Trace Formula), where K is a perfect field of characteristics not equal to 2. We prove how several classic combinatorial results are particular instances of a Trace (Inversion) Formula in finite $$\mathbb {Q}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Q</mml:mi> </mml:math> -algebras. This is the case with the Exclusion-Inclusion Principle (in its general form, both with direct and reverse order associated to subsets inclusion). This approach also allows us to exhibit a basis of the space of null t -designs, which differs from the one described in Theorem 4 of Deza and Frankl (Combinatorica 2:341–345, 1982). Provoked by the elegant proof (which uses no induction) in Frankl and Pach (Eur J Comb 4:21–23, 1983) of the Sauer–Shelah–Perles Lemma, we produce a new one based only in duality in the $$\mathbb {Q}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Q</mml:mi> </mml:math> -algebra $$\mathbb {Q}[V_n]$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Q</mml:mi> <mml:mo>[</mml:mo> <mml:msub> <mml:mi>V</mml:mi> <mml:mi>n</mml:mi> </mml:msub> <mml:mo>]</mml:mo> </mml:mrow> </mml:math> of polynomials functions defined on the zero-dimensional algebraic variety of subsets of the set $$[n]:=\{1,2,\ldots , n\}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>[</mml:mo> <mml:mi>n</mml:mi> <mml:mo>]</mml:mo> <mml:mo>:</mml:mo> <mml:mo>=</mml:mo> <mml:mo>{</mml:mo> <mml:mn>1</mml:mn> <mml:mo>,</mml:mo> <mml:mn>2</mml:mn> <mml:mo>,</mml:mo> <mml:mo>…</mml:mo> <mml:mo>,</mml:mo> <mml:mi>n</mml:mi> <mml:mo>}</mml:mo> </mml:mrow> </mml:math> . All results are equally true if we replace $$\mathbb {Q}[V_n]$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Q</mml:mi> <mml:mo>[</mml:mo> <mml:msub> <mml:mi>V</mml:mi> <mml:mi>n</mml:mi> </mml:msub> <mml:mo>]</mml:mo> </mml:mrow> </mml:math> by $$K[V_n]$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>K</mml:mi> <mml:mo>[</mml:mo> <mml:msub> <mml:mi>V</mml:mi> <mml:mi>n</mml:mi> </mml:msub> <mml:mo>]</mml:mo> </mml:mrow> </mml:math> , where K is any perfect field of characteristics $$\not =2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>≠</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:math> . The article connects results from two fields of mathematical knowledge that are not usually connected, at least not in this form. Thus, we decided to write the manuscript in a self-contained survey-like style, although it is not a survey paper at all. Readers familiar with Commutative Algebra probably know most of the proofs of the statements described in section 2. We decided to include these proofs for those potential readers not so familiar with this framework.
The rise of modern cryptographic protocols such as Zero-Knowledge proofs and secure Multi-party Computation has led to an increased demand for a new class of symmetric primitives. Unlike traditional platforms such as servers, microcontrollers, and desktop computers, these primitives are designed to be implemented in arithmetical circuits. In terms of security evaluation, arithmetization-oriented primitives are more complex compared to traditional symmetric cryptographic primitives. The arithmetization-oriented permutation Grendel employs the Legendre Symbol to increase the growth of algebraic degrees in its nonlinear layer. To analyze the security of Grendel thoroughly, it is crucial to investigate its resilience against algebraic attacks. This paper presents a preimage attack on the sponge hash function instantiated with the complete rounds of the Grendel permutation, employing algebraic methods. A technique is introduced that enables the elimination of two complete rounds of substitution permutation networks (SPN) in the sponge hash function without significant additional cost. This method can be combined with univariate root-finding techniques and Gröbner basis attacks to break the number of rounds claimed by the designers. By employing this strategy, our attack achieves a gain of two additional rounds compared to the previous state-of-the-art attack. With no compromise to its security margin, this approach deepens our understanding of the design and analysis of such cryptographic primitives.
Double auctions are procedures to trade commodities such as electricity or parts of the wireless spectrum at optimal prices. Buyers and sellers inform the auctioneer what quantity they want to buy or sell at specific prices. The auctioneer aggregates these offers into demand and supply curves and finds the intersection representing the optimal price. In this way, commodities exchange owners in an economically-efficient manner. Ideally, the auctioneer is a trusted third party that does not abuse the information they gain. However, the offers reveal sensitive information about the traders, which the auctioneer may use for economic gain as insider information. These concerns are not theoretical; investigations against auctioneers in electricity and advertisement auctions for manipulating auctions are ongoing. These concerns call for solutions that conduct double auctions in a privacy-preserving and verifiable way. However, current solutions are impractical: To the best of our knowledge, the only solutions satisfying these properties require full interaction of all participants. In this work, we design a more practical solution. We propose the first privacy-preserving and verifiable double auction scheme that does not require traders to interact actively, tailored to electricity trading on (inter)national exchanges. Our solution relies on homomorphic encryption, commitments, and zero-knowledge proofs. In a simulated auction with 256 traders, we observe that traders take up to 10 seconds to generate their order, the auctioneer takes 10 seconds to verify an order, and the auction result is computed and verified in 30 seconds. We extrapolate these results to larger auctions to show the practical potential.
Evaluating1 the popularity of content, developing personalized recommendation algorithms, and optimizing advertising revenue are crucial aspects of Over-the-Top (OTT) media content services. In order to achieve these goals, accurate viewership measurement of OTT content is essential. However, due to the stringent security policies of mobile platforms, it has been challenging to propose an easy and reliable method for measuring viewership. In this paper, we propose an efficient and secure viewership measurement technique for OTT content on the iOS platforms. The proposed technique utilizes audio filtering and zero-knowledge proof techniques to address the challenges. By leveraging audio filtering, the content can be quickly identified, enabling accurate viewership measurement. Additionally, the use of zero-knowledge proof ensures the protection of users' personal information, preventing indiscriminate acquisition of user data in OTT services.
Aydin Abadi, Dan Ristea, Artem Grigor, Steven J. Murdoch
Time-Lock Puzzles (TLPs) enable a client to lock a message such that a server can unlock it only after a specified time. They have diverse applications, such as scheduled payments, secret sharing, and zero-knowledge proofs. In this work, we present a scalable TLP designed for real-world scenarios involving a large number of puzzles, where clients or servers may lack the computational resources to handle high workloads. Our contributions are both theoretical and practical. From a theoretical standpoint, we formally define the concept of a “Delegated Time-Lock Puzzle (D-TLP)”, establish its fundamental properties, and introduce an upper bound for TLPs, addressing a previously overlooked aspect. From a practical standpoint, we introduce the “Efficient Delegated Time-Lock Puzzle” (ED-TLP) protocol, which implements the D-TLP concept. This protocol enables both the client and server to securely outsource their resource-intensive tasks to third-party helpers. It enables realtime verification of solutions and guarantees their delivery within predefined time limits by integrating an upper bound and a fair payment algorithm. ED-TLP allows combining puzzles from different clients, enabling a solver to process them sequentially, significantly reducing computational resources, especially for a large number of puzzles or clients. ED-TLP is the first protocol of its kind. We have implemented ED-TLP and conducted a comprehensive analysis of its performance for up to 10,000 puzzles. The results highlight its significant efficiency in TLP applications, demonstrating that EDTLP securely delegates 99% of the client’s workload and 100% of the server’s workload with minimal overhead.
Crowdsourcing has emerged as a prevalent method for mitigating the risks of correctness and security in outsourced cloud computing. This process involves an aggregator distributing tasks, collecting responses, and aggregating outcomes from multiple data sources. Such an approach harnesses the wisdom of crowds to accomplish complex tasks, enhancing the accuracy of task completion while diminishing the risks associated with the malicious actions of any single entity. However, a critical question arises: How can we ensure that the aggregator performs its role honestly and each contributor's input is fairly evaluated? In response to this challenge, we introduce a novel protocol termed $\mathsf{zkTI}. This scheme guarantees both the honest execution of the aggregation process by the aggregator and the fair evaluation of each data source. It innovatively integrates a cryptographic construct known as zero-knowledge proof with a category of truth inference algorithms for the first time. Under this protocol, the aggregation operates with both correctness and verifiability, while ensuring fair assessment of data source reliability. Experimental results demonstrate the protocol's efficiency and robustness, making it a viable and effective solution in crowdsourcing and cloud computing.
Electronic voting systems have the potential to improve the efficiency and accessibility of elections, but they also introduce unique challenges in terms of security, privacy, and voter anonymity. In this paper, we propose a secure and privacy-preserving voting system based on zero-knowledge proofs and homomorphic encryption. Our system ensures the integrity, confidentiality, and authenticity of votes while preserving the anonymity of voters. We present the system architecture, design, and implementation, along with a detailed analysis of the cryptographic techniques employed. The evaluation of our proposed system demonstrates its effectiveness, efficiency, and scalability, making it suitable for use in large-scale elections. This work contributes to the ongoing efforts to develop more secure, transparent, and accessible electronic voting systems for the future.
Blockchain-based decentralized identity management provides a promising solution to improve the security and privacy of healthcare systems and make them scalable. Traditional Identity Management Systems are centralized, which makes them single-point-of-failure, vulnerable to attacks and data breaches, and non-scalable. In contrast, decentralized identity management based on the blockchain can ensure secure and transparent access to patient data while preserving privacy. This approach enables patients to control their personal health data while granting permission for medical personnel to access specific information as needed. We propose a decentralized identity management system for healthcare systems named BDIMHS based on a permissioned blockchain with Hyperledger Indy and Hyperledger Aries. We develop further descriptions of required functionalities and provide high-level procedures for network initialization, enrollment, registration, issuance, verification and revocation functionalities. The proposed solution improves data security, privacy, immutability, interoperability, and patient autonomy by using selective disclosure, zero-knowledge proofs, Decentralized Identifiers, and Verifiable Credentials. Furthermore, we discuss the potential challenges associated with implementing this technology in healthcare and evaluate the performance and security of the proposed solution.
Haochen Sun, Tonghe Bai, J. Li, Change Institutions to: University of Waterloo
The recent advancements in deep learning have brought about significant changes in various aspects of people’s lives. Meanwhile, these rapid developments have raised concerns about the legitimacy of the training process of deep neural networks. To protect the intellectual properties of AI developers, directly examining the training process by accessing the model parameters and training data is often prohibited for verifiers. In response to this challenge, we present zero-knowledge deep learning (zkDL), an efficient zero-knowledge proof for deep learning training. To address the long-standing challenge of verifiable computations of non-linearities in deep learning training, we introduce zkReLU, a specialized proof for the ReLU activation and its backpropagation. zkReLU turns the disadvantage of non-arithmetic relations into an advantage, leading to the creation of FAC4DNN, our specialized arithmetic circuit design for modelling neural networks. This design aggregates the proofs over different layers and training steps, without being constrained by their sequential order in the training process. With our new CUDA implementation that achieves full compatibility with the tensor structures and the aggregated proof design, zkDL enables the generation of complete and sound proofs in less than a second per batch update for an 8-layer neural network with 10M parameters and a batch size of 64, while provably ensuring the privacy of data and model parameters. To our best knowledge, we are not aware of any existing work on zero-knowledge proof of deep learning training that is scalable to million-size networks.
Electron energy-loss spectroscopy (EELS) and cathodoluminescence (CL) are both powerful tools for the optical characterization of materials such as plasmonic and resonant dielectric nano-structures, probing electronic transitions and the local photonic density of states with nanometric spatial resolution [1]. Up to now, the correlations between electron energy-loss and photon generation have only scarcely been considered, which however has huge potential of increasing measurements sensitivity as recently demonstrated for x-ray & core-loss EELS [2]. In this work, we demonstrate two-order of magnitude contrast enhanced cavity mode imaging enabled by the generation and coincident detection of energy-shifted electrons and intracavity photons, produced in a spontaneous scattering process [3]. We combine a transmission electron microscope (TEM) with a fibre-coupled high-Q silicon nitride (Si3N4) resonator with top air cladding, enabling access to the optical near field for free electrons. The continuous electron beam at 120keV with 25nm focal diameter is passed by the ring resonator in an aloof geometry visualized in Fig. 1a. The stream of single electrons interacts with the vacuum fields of the waveguide, resulting in the generation of single photons by inelastic electron-light scattering [4,5]. In this spontaneous process the electron will lose the corresponding photon quanta of energy. We achieve coincidence detection of generated photons and energy-shifted electrons by employing a single-photon avalanche diode and an event-based electron detector behind an imaging spectrometer (cf. Fig 1a). Analysing the correlation data in time delay to the next photon event and electron energy, we observe a time-independent uncorrelated background around zero energy-loss and a strong coincidence peak at zero time-delay and an electron energy-loss of 0.8 eV, corresponding to a generated photon wavelength around 1550 nm (cf. Fig. 1b). The latter demonstrates the measurement of correlated electron-photon pairs on a single particle level. These pairs can be harnessed for correlation-enhanced imaging by enabling the separation of physical scattering events from independent noise at the detectors. In a proof of concept experiment we demonstrate correlation-enhanced mapping of an optical mode's exponential decay in vacuum. To this end, we scan the focused electron beam across the area in front of the resonator's waveguide and perform an electron-photon correlation measurement for every beam position. When analysing the electron and photon data separately, we observe the known behaviour of tracing the exponential decay up to a point where the detector counts level off at a constant background value, thereby limiting the dynamic range of the measurement (cf. Fig. 1c, blue and orange data). In contrast, the correlated events resolve the evanescent decay of the cavity field over longer distances, due to the strongly reduced background (cf. Fig. 1c, purple). Including the slight decrease in signal intensity, this corresponds to a two-order of magnitude improved dynamic range. In conclusion, we demonstrate contrast-enhanced optical cavity mode imaging, by harnessing the generation and detection of electron-photon pairs. This quantum enhanced imaging allows background-suppression in optical field measurements of nano-structures without requiring prior knowledge of the noise causing processes. Additionally, it improves the differentiation between CL pathways [6]. Moreover, the generation and detection of electron-photon pairs constitutes a crucial step towards future experiments on the quantum nature of free electron-light interactions, investigating the entanglement between photons and electrons. Correlation-enhanced cavity mode imaging. a) Experimental setup: Free electrons in a continuous electron beam traverse a fibre-coupled high-Q Si3N4 microring resonator. In a spontaneous scattering process a photon is emitted into a resonator mode, while the electron experiences energy loss. The generated photons are detected with a single photon counter and the electron energy and arrival time are analysed with an event-based electron detector behind an imaging spectrometer. Both signals are considered in a coincidence scheme, with the photon arrival time used for time tagging. b) Correlation histogram over the electron energy and relative time delay to a photon event, showing a clear coincidence peak at an energy-loss of one photon energy and zero time-delay. c) Imaging of the distant dependent exponential decay of an optical resonator mode. Every data point is acquired by integrating over a line parallel to the resonator's surface. The correlated events show a much smaller background and, thus, a higher dynamic range (DR) compared to the sole electron data and the sole photon data.