We study the relationship between problems solvable by quantum algorithms in polynomial time and those for which zero-knowledge proofs exist. In prior work, Aaronson [arxiv:quant-ph/0111102] showed an oracle separation between BQP and SZK, i.e. an oracle $A$ such that $\mathrm{SZK}^A \not\subseteq \mathrm{BQP}^A$. In this paper we give a simple extension of Aaronson's result to non-interactive zero-knowledge proofs with perfect security. This class, NIPZK, is the most restrictive zero-knowledge class. We show that even for this class we can construct an $A$ with $\mathrm{NIPZK}^A \not\subseteq \mathrm{BQP}^A$.
We study the relationship between problems solvable by quantum algorithms in\npolynomial time and those for which zero-knowledge proofs exist. In prior work,\nAaronson [arxiv:quant-ph/0111102] showed an oracle separation between BQP and\nSZK, i.e. an oracle $A$ such that $\\mathrm{SZK}^A \\not\\subseteq\n\\mathrm{BQP}^A$. In this paper we give a simple extension of Aaronson's result\nto non-interactive zero-knowledge proofs with perfect security. This class,\nNIPZK, is the most restrictive zero-knowledge class. We show that even for this\nclass we can construct an $A$ with $\\mathrm{NIPZK}^A \\not\\subseteq\n\\mathrm{BQP}^A$.\n
A key challenge in 4G and emerging 5G systems is that of reliably detecting the uplink transmissions of users close to the edge between cells. These users are subject to significant signal attenuation due to path loss, and frequent hand-off from one cell to the other, making channel estimation very challenging. Even multiuser detection using base station cooperation often fails to detect such users, due to channel estimation errors and the sensitivity of multiuser detection to near-far power imbalance. Is it even possible to reliably decode the cell-edge users' signals under these circumstances? This paper shows, perhaps surprisingly, that with a suitable base station `interferometry' strategy, the cell-edge users' signals can be reliably decoded at low SNR under mild conditions. Exploiting the fact that cell-edge users' signals are weak but common to both base stations, while users close to a base station are unique to that base station, reliable detection is enabled by Canonical Correlation Analysis (CCA) - a machine learning technique that reliably estimates a common subspace, even in the presence of strong individual interference. Free from cell-center interference, the resulting mixture of cell-edge signals can then be unraveled using well-known algebraic signal processing techniques. Simulations demonstrate that the proposed detector achieves order of magnitude BER improvement compared to an `oracle' zero-forcing with successive interference cancellation that assumes perfect knowledge of all channels. The paper also includes proof of common subspace identifiability for the assumed generative model, which was curiously missing from the machine learning / CCA literature.
Blockchain has been treated as one of the most promising technologies to promote crowdsourcing by providing new nice features, such as decentralization and accountability. Unfortunately, some inherent limitations of blockchain have been rarely addressed by the most existing works when applying blockchain into crowdsourcing, which becomes the performance bottleneck of crowdsourcing systems. In this paper, we propose a novel hybrid blockchain crowdsourcing platform to achieve decentralization and privacy preservation. Our platform integrates with a hybrid blockchain structure, dual-ledgers, and dual consensus algorithms to ensure secure communication between the requesters and the workers. Moreover, the smart contract and zero-knowledge proof are employed to ensure automatic operation of the tasks and the protection users' privacy, respectively. Finally, we conduct experiments to confirm the efficiency of the adopted consensus algorithm on our platform by comparing it with the state-of-the-art.
The importance and usage of the distributed cloud is increasing rapidly over a traditionally centralized cloud for the storing and exchanging of digital assets between untrusted parties in many business sectors. Storing the digital assets in the distributed cloud is considered superior to traditional cloud computing in terms of environmentally friendly, cost, security and other technical dimensions. In this article, a contemporary architecture DistProv is proposed where an open source distributed cloud IPFS is used to store and transfer the digital assets between the consignor and consignee. These two are untrusted parties exchanging sensitive documents secured by cryptographic algorithms with permission-based access verified by ethereum smart contracts using zero-knowledge proof (ZKP) and simultaneously publishing the provenance data about the digital asset as a transaction on the blockchain. This article also discusses on verifying the integrity of the digital assets and authentication of the consignor and thus preserving a strong CIA triad.
The emerging blockchain technology, powered by the smart contract functionality, is expected to revolutionize traditional systems by decentralization and autonomy. When the blockchain technology is applied in real-life systems, a smart contract may need to take in sensitive data to execute its code. For example, a decentralized medical insurance smart contract needs access to personal health data. Therefore, it is crucial to guarantee both privacy and authenticity of data sent to the smart contract, so that everyone can verify data without leaking sensitive information. Currently, only few works have tried to achieve privacy and authenticity at the same time. In this work, we first propose zk-DASNARK, a zero-knowledge SNARK scheme for authenticated data. It is designed by combining the zk-SNARK technique with digital signature in an effective way. Based on zk-DASNARK, we design zk-AuthFeed, a zero-knowledge authenticated data feed scheme to achieve both data privacy and authenticity for smart contract. We implement zk-AuthFeed and conduct comprehensive experiments on Ethereum. The experiments show that zk-AuthFeed is highly efficient: key generation takes about 7 seconds only, proof generation takes less than 2 seconds, and proof verification takes less than 40 ms.
In this paper, we have achieved privacy protection and high transparency in a permissioned blockchain. There is a sidechain that connects the permissionless blockchain and the permissioned blockchain. The behavior in the permissioned blockchain is almost a black box from the perspective of the permissionless blockchain. While this fact is useful for privacy protection, there is room for improvement in terms of transparency. To improve the transparency of the permissioned blockchain under privacy protection, we consider traceability in the permissioned blockchain consisting of the following three properties: trade privacy (who trades with whom and at what asset amount), preservation (the total amount inside the permissioned blockchain, including deposits and withdrawals to the permissionless blockchain, is immutable), and noninvolvement (some members in the permissioned blockchain are not involved in some trades, and it is possible to prove that specified members performed the transaction). To the best of our knowledge, we are the first to achieve both preservation and noninvolvement while protecting the privacy of transactions. Our approach is as follows. We model traceability based on the hidden Markov model. Because the proof of traceability requires the calculation of more than quadratic degrees, we encrypt this model by homomorphic encryption. The number of participants in the permissioned blockchain corresponds to the number of additions in the model. Then, we can construct the encrypted model by employing somewhat homomorphic encryption. The establishment of the original model is verifiable by applying the noninteractive zero-knowledge proof of the knowledge that the plaintext is equal to zero. This is an adaptation of Benhamouda et al. (Asiacrypt 2014).
Block chain technology, while revolutionizing various sectors, faces significant challenges regarding data privacy and security. As block chain networks become more widespread, the need for privacy-preserving techniques becomes critical to ensure the confidentiality, integrity, and anonymity of user data. This article reviews various privacy-enhancing techniques implemented in block chain networks, including cryptographic protocols, zero-knowledge proofs, and off-chain solutions. The aim is to identify their effectiveness, limitations, and the trade-offs between privacy and performance. Through a comprehensive analysis, this study explores existing methodologies and suggests potential improvements for safeguarding privacy while maintaining the decentralized and transparent nature of block chain systems.
Zero-knowledge proofs have become an important tool for addressing privacy and scalability concerns in cryptographic protocols. For zero-knowledge proofs used in blockchain applications, it is desirable to have small proof sizes and fast verification. Yet by design, existing constructions with these properties such as zk-SNARKs also have a secret trapdoor embedded in a relation dependent structured reference string (SRS). Knowledge of this trapdoor suffices to break the security of these proofs. The SRSs required by zero-knowledge proofs are usually constructed with multiparty computation protocols, but the resulting parameters are specific to each individual circuit. In this thesis, we propose a model for constructing zero-knowledge arguments (i.e. zero-knowledge proofs with computational soundness) in which the generation of the SRS is directly considered in the security analysis. In our model the same SRS can be used across multiple applications. Further, the model is updatable i.e. users can update the universal SRS and the SRS is considered secure provided at least one of these users is honest. We propose two zero-knowledge arguments with updatable and universal SRSs, as well as a third which is neither updatable nor universal, but which through similar techniques achieves simulation extractability. The proposed arguments are practical, with proof sizes never more than a constant number of group elements. Verification for two of our constructions consist of a small number of pairing operations. For our other construction, which has the desirable property of a linear sized updatable and universal SRS, we describe efficient batching techniques so that verification is fast in the amortised setting.
Ride-sharing is a service that enables drivers to share trips with other riders, contributing to appealing benefits of shared travel cost and reducing traffic congestion. However, the majority of existing ride-sharing services rely on a central third party to organize the service, which make them subject to a single point of failure and privacy disclosure concerns by both internal and external attackers. Moreover, they are vulnerable to distributed denial of service (DDoS) and Sybil attacks launched by malicious users and external attackers. Besides, high service fees are paid to the ride-sharing service provider. In this paper, we propose a decentralized ride-sharing service based on public Blockchain, named B-Ride. B-Ride enables drivers to offer ride-sharing services without relying on a trusted third party. Both riders and drivers can learn whether they can share rides while preserving their trip data, including pick-up/drop-off location, departure/arrival date and travel price. However, malicious users exploit the anonymity provided by the public blockchain to submit multiple ride requests or offers, while not committing to any of them, in order to find a better offer or to make the system unreliable. B-Ride solves this problem by introducing a time-locked deposit protocol for a ride-sharing by leveraging smart contract and zero-knowledge set membership proof. In a nutshell, both a driver and a rider have to show their good will and commitment by sending a deposit to the blockchain. Later, a driver has to prove to the blockchain on the agreed pick-up time that he/she arrived at the pick-up location on time. To preserve rider/driver privacy by hiding the exact pick-up location, the proof is performed using zero-knowledge set membership proof. Moreover, to ensure fair payment, a pay-as-you-drive methodology is introduced based on the elapsed distance of the driver and rider. In addition, we introduce a reputation model to rate drivers based on their past behaviour without involving any third-parties to allow riders to select them based on their history on the system. Finally, we implement our protocol and deploy it in a test net of Ethereum. The experimental results show the applicability of our protocol atop existing real-world blockchains.
Ride-sharing is a service that enables drivers to share their trips with\nother riders, contributing to appealing benefits of shared travel costs.\nHowever, the majority of existing platforms rely on a central third party,\nwhich make them subject to a single point of failure and privacy disclosure\nissues. Moreover, they are vulnerable to DDoS and Sybil attacks due to\nmalicious users involvement. Besides, high fees should be paid to the service\nprovider. In this paper, we propose a decentralized ride-sharing service based\non public Blockchain, named B-Ride. Both riders and drivers can find rides\nmatch while preserving their trip data, including pick-up/drop-off location,\nand departure/arrival date. However, under the anonymity of the public\nblockchain, a malicious user may submit multiple ride requests or offers, while\nnot committing to any of them, to discover better offer or to make the system\nunreliable. B-Ride solves this problem by introducing a time-locked deposit\nprotocol for a ride-sharing by leveraging smart contract and zero-knowledge set\nmembership proof. In a nutshell, both a driver and a rider have to show their\ncommitment by sending a deposit to the blockchain. Later, a driver has to prove\nto the blockchain on the agreed departure time that he has arrived at the\npick-up location. To preserve rider/driver location privacy by hiding the exact\npick-up location, the proof is done using zero-knowledge set membership\nprotocol. Moreover, to ensure a fair payment, a pay-as-you-drive methodology is\nintroduced based on the elapsed distance of the driver and the rider. Also, we\nintroduce a reputation-based trust model to rate drivers based on their past\ntrips to allow riders to select them based on their history on the system.\nFinally, we implement B-Ride in a test net of Ethereum. The experiment results\nshow the applicability of our protocol atop the existing real-world blockchain.\n
Advanced Information Technology and Services: OTS 2019: Proceedings of the Twenty-fourth Conference, 18th - 19th of June, 2019. The papers in the proceedings of the 24th Professional Conference on Advanced Information Technology and Services address the extremely topical challenges that we (IS/IT experts, Software Engineers, Computer Scientists, Data Scientists, software and solution architects, developers, IT managers, etc.) encounter in our daily work. The authors present the innovative solutions and rich experience gained by conducting real-life projects: Applying Augmented Intelligence and Machine Learning technologies, Using Blockchain technologies and platforms, Developing loosely coupled micro-services, Providing full virtualization and exploitation of distributed infrastructures, Ensuring cybersecurity, confidentiality and privacy, Applying large-scale agile methods in distributed teams, Introducing agile approaches that enable the rapid and efficient software development via automated processes, and continuous testing, integration, delivery & deployment Updating and upgrading existing Information Systems, Incorporating advanced programming languages and development environments, Developing user-friendly web and mobile solutions & services.
The European rabbit (Oryctolagus cuniculus) is one of the most successful invasivemammals in Australia, causing substantial economic losses in agriculture and damage tothe environment. The Lockyer Valley in South East Queensland is an important vegetablegrowing region in Australia. Unlike most other regions of Australia where rabbits have beenan endemic problem for a long time, rabbits invaded this region in 2009, causing increasingcrop losses. Many rabbit control methods are available to vegetable growers, but there is norabbit-density threshold available for managing damage to vegetable crops because little isknown of how different densities of rabbits reduce crop yields. In this thesis, I aim todetermine the density thresholds for managing rabbit damage to broccoli and corn crops,and to understand how the broccoli plant compensates for damage. This information willassist vegetable growers in developing an effective management strategy for rabbit control.Known densities of rabbits (0, 3.75, 7.5, 15 and 30 rabbits per hectare) of rabbits wereintroduced into broccoli crops for a predetermined period of time (24 days) at different plantdevelopment stages (single-point damage), and yield losses caused by rabbits weremeasured. The study was conducted in rabbit and predator-proof enclosure at TheUniversity of Queensland (UQ) Gatton campus in 2014 and 2015. When rabbits wereintroduced to broccoli at the seedling stage (14 days after transplanting [DAT]), therelationship between introduced rabbit density (DI) and yield loss (YL) was linear, with YLincreasing with DI. When rabbits were introduced at the establishment stage (28 DAT), therewas no significant relationship between DI and YL. Thus, rabbit control is most critical at theseedling stage. The density threshold (DT) was estimated based on the relationship betweenDI and YL at the seedling stage. DT varied depending on the effectiveness of the controlmethod in reducing DI and on the cost of control as a percentage of the farm-gate value ofbroccoli. For example, DT would need to be 6.54 rabbits per hectare for triggering RABBAIT®1080 carrot baiting, if this method was effective in reducing DI by 94% and if the cost ofbaiting was 1.01% of the farm-gate value of broccoli.To assess the ability of broccoli crops to compensate for damage caused by rabbits,simulated rabbit damage was performed under greenhouse conditions at UQ Gattoncampus from June 2015 to January 2016. Part of each leaf (equivalent to 5%, 10%, 25%,50% and 80%) from each plant was removed manually to simulate these levels of canopydamage at the seedling stage (5 leaves, 17 DAT), establishment stage (7 leaves, 28 DAT) and heading stage (11 leaves, 47 DAT). When damage was imposed at the establishmentand heading stages, the broccoli plants could completely compensate for the damage andmaintain yield. Broccoli that was damaged at the earlier stages of development did notcompletely recover from damage before harvest.To assess the effects of rabbits grazing on corn, an experiment was conducted at rabbit-and predator-proof enclosures on the UQ Gatton campus over the summer cropping seasonin 2016. Corn was grown in 14 enclosures following current agronomic procedures, and wassubjected to grazing by 2 densities of rabbits (44.44 rabbits per hectare and 88.89 rabbitsper hectare) in 3 different growth stages: emergence (7 days after sowing [DAS]), tillering(21 DAS) and tassel (42 DAS) over 7 days (single-point damage). In addition, in oneenclosure zero rabbits were kept, and in another enclosure 2 rabbits were kept continually.Rabbit grazing resulted in a significant decrease in the numbers of plants at the emergencestage, Also, the number of ears of corn per pen was significantly reduced by rabbit grazing.The emergence stage is the critical stage to control rabbits as rabbit grazing resulted in thehighest losses in corn production during the early growth season. This knowledge providesfarmers with a better understanding of the damage caused by rabbits and allows them tomake informed decisions as to whether their crop needs to be protected from rabbits, andwhen rabbits should be managed.These results highlight the need to monitor DI before planting and in the early stages ofplanting (seedling stage of broccoli and emergence stage of corn). The DT estimated in thisthesis will provide the basis for making economically informed decisions on the managementof rabbit damage to broccoli and corn crops. Future studies are required to verify these DT,using free ranging rabbits in the field.
With the development of cloud computing technology, data can be outsourced to the cloud and conveniently shared among users. However, in many circumstances, users may have concerns about the reliability and integrity of their data. It is crucial to provide data sharing services that satisfy these security requirements. We introduce a reliable and secure data sharing scheme, using the threshold secret sharing technique and the Chaum-Pedersen zero-knowledge proof. The proposed scheme is not only effective and flexible, but also able to achieve the semantic security property. Moreover, our scheme is capable of ensuring accountability of users’ decryption keys as well as cheater identification if some users behave dishonestly. The efficiency analysis shows that the proposed scheme has a better performance in terms of computational cost, compared with the related work. It is particularly suitable for application to protect users’ medical insurance data over the cloud.
With the growth in popularity for cryptocurrencies the need for privacy preserving blockchains is growing as well. Zcash is such a blockchain, providing transaction privacy through zero-knowledge proofs. In this paper we analyze transaction linkability in Zcash based on the currency minting transactions (mining). Using predictable usage patterns and clustering heuristics on mining transactions an attacker can link to publicly visible addresses over 84% of the volume of the transactions that use a ZK-proof. Since majority of Zcash transactions are not yet using ZK-proofs, we show that overall 95.5% of the total number of Zcash transactions are potentially linkable to public addresses by just observing the mining activity.
Darya Korepanova, Maria Nosyk, Alex Ostrovsky, Yury Yanovich
Zero-knowledge proofs are an emerging cryptographic technology that have many potential applications for blockchains. Exonum is an extensible open-source framework for creating blockchain applications. In this article, we describe how zero-knowledge proofs, specifically bulletproofs, can be applied to build a privacy-focused service using Exonum. The token logic is implemented as a platform service and is a proof of concept.
Donghui Ding, Kang Li, Linpeng Jia, Zhongcheng Li · 6 authors
The blockchain technology has been applied to wide areas. However, the open and transparent properties of the blockchains pose serious challenges to users' privacy. Among all the schemes for the privacy protection, the zero-knowledge proof algorithm conceals most of the private information in a transaction, while participants of the blockchain can validate this transaction without the private information. However, current schemes are only aimed at blockchains with the UTXO model, and only one type of assets circulates on these blockchains. Based on the zero-knowledge proof algorithm, this paper proposes a privacy protection scheme for blockchains that use the account and multi-asset model. We design the transaction structure, anonymous addresses and anonymous asset metadata, and also propose the methods of the asset transfer and double-spending detection. The zk-SNARKs algorithm is used to generate and to verify the zero-knowledge proof. And finally, we conduct the experiments to evaluate our scheme.
Hui Kang, Ting Dai, Nerla Jean-Louis, Shu Tao · 5 authors
On a Blockchain network, transaction data are exposed to all participants. To preserve privacy and confidentiality in transactions, while still maintaining data immutability, we design and implement FabZK. FabZK conceals transaction details on a shared ledger by storing only encrypted data from each transaction (e.g., payment amount), and by anonymizing the transactional relationship (e.g., payer and payee) between members in a Blockchain network. It achieves both privacy and auditability by supporting verifiable Pedersen commitments and constructing zero-knowledge proofs. FabZK is implemented as an extension to the open source Hyperledger Fabric. It provides APIs to easily enable data privacy in both client code and chaincode. It also supports on-demand, automated auditing based on encrypted data. Our evaluation shows that FabZK offers strong privacy-preserving capabilities, while delivering reasonable performance for the applications developed based on its framework.
A thermally activated absorption heat pump suitable for use in naval expeditionary Environmental Control Units, as well as residential space-conditioning, is developed. Waste heat characteristic of the exhaust stream from a diesel engine GenSet is used to drive an absorption cycle to provide cooling. The heat source is coupled to the heat pump using an intermediate fluid loop for flexible deployment. With minor modifications, the heat pump could also provide heating at high coefficients of performance, resulting in versatile functionality. This technology capitalizes on heat and mass transfer enhancement possible in microscale passages to provide a compact architecture for the components and the overall system. The working fluid pair with zero Global Warming Potential is contained within this assembly, reducing fluid inventories significantly over conventional systems. Quiet, reliable, long-life operation due to the absence of a compressor and the use of few moving parts are further critical distinguishing advantages. Modularity in cooling capacity has been demonstrated through scaling-up of component geometry and internal features and dimensions. The core technology was initially demonstrated with a proof-of-concept microscale absorption chiller measuring 200 × 200 × 34 mm and weighing 7 kg that delivered 300 W of cooling in laboratory tests. In the previous BEETIT project, the team made significant advances over the proof-of-concept. System and component designs with > 10× scale-up in capacity were developed, in a packaged unit capable of standalone operation with a semi-autonomous control system. A cooling capacity of 3.5 kW with a COP > 0.5 at an ambient temperature of 35°C was demonstrated for this natural gas-fired unit. Significant cost reductions in fabrication were achieved using low-cost brazing instead of diffusion bonding. In companion projects funded by the Southern Company and the Georgia Research Alliance, stamping and fluid forming techniques were investigated to fabricate microscale features instead of photochemical etching, thereby leading to significant cost reductions. In a follow-on effort funded by ARPA-E and NAVFAC, a 2.7 kW cooling unit was developed to provide cooling at a severe ambient condition of 51.7°C. The unit was driven directly by diesel engine exhaust heat. Innovative finned heat and mass exchangers for the ambient-coupled condenser and absorber were developed. In the present effort, a standalone, packaged and controllable 10.5 kW cooling capacity absorption chiller is developed. This demonstrates a 30× scale up from the proof-of-concept, thus validating the scalability of microchannel heat exchangers for absorption heat pumps. Autonomous operation algorithms demonstrated enhanced dynamic performance. The knowledge from previous projects was leveraged to develop novel component designs that further helped in miniaturizing the heat exchangers. All coupling fluids are hydronically coupled to aid flexible field deployment. The prototype unit provides design cooling capacity at high ambient temperature conditions of 44°C at COP > 0.6.
Open access
Advanced Thermodynamic Systems and Engines
Refrigeration and Air Conditioning Technologies
Thermodynamic and Exergetic Analyses of Power and Cooling Systems
A zero-knowledge proof is a fundamental cryptographic primitive that enables the verification of statements without revealing unnecessary information. Zero-knowledge proofs are a key component of many cryptographic protocols and, often, one of their main efficiency bottlenecks. In recent years there have been great advances in improving the efficiency of zero-knowledge proofs, bring them closer to wide deployability. In this thesis we make another step towards the construction of computationally-efficient zero-knowledge proofs. Specifically, we construct efficient zero-knowledge proofs for the satisfiability of arithmetic circuits for which the computational cost of the prover is only a constant factor more expensive than direct evaluation of the circuit. We also construct efficient zero-knowledge proofs to check the correct execution of (Tiny)RAM programs. In this case the computational cost for the prover is a superconstant factor larger than executing the program directly. Our proofs also support efficient verification and small proof sizes. For security, they rely on symmetric primitives and could potentially withstand attacks from quantum computers. On a different research direction, we look at group signatures, a fundamental primitive which relies on zero-knowledge proofs. A group signature enables users to sign anonymously on behalf of a group of users. In case of dispute a Manager can identify the author of a signature and potentially banish the user from the group. In this thesis we address the fundamental question of defining the security of fully dynamic group signatures, for which the users can join and leave at any time. Differently from other restricted settings, this case has been largely overlooked in the past. Our security model is general, does not implicitly assume existing design paradigms and captures the security of existing models for more restricted settings.
In this work we consider the interplay between multiprover interactive proofs, quantum entanglement, and zero knowledge proofs - notions that are central pillars of complexity theory, quantum information and cryptography. In particular, we study the relationship between the complexity class MIP*, the set of languages decidable by multiprover interactive proofs with quantumly entangled provers, and the class PZK-MIP*, which is the set of languages decidable by MIP* protocols that furthermore possess the perfect zero knowledge property. Our main result is that the two classes are equal, i.e., MIP* = PZK-MIP*. This result provides a quantum analogue of the celebrated result of Ben-Or, Goldwasser, Kilian, and Wigderson (STOC 1988) who show that MIP = PZK-MIP (in other words, all classical multiprover interactive protocols can be made zero knowledge). We prove our result by showing that every MIP* protocol can be efficiently transformed into an equivalent zero knowledge MIP* protocol in a manner that preserves the completeness-soundness gap. Combining our transformation with previous results, we obtain the corollaries that i) all languages that can be solved in non-deterministic double exponential time have zero knowledge MIP* protocols and ii) all co-recursively enumerable languages (which include undecidable problems as well as all decidable problems) have zero knowledge MIP* protocols with vanishing promise gap.
Lasse Herskind, Alberto Giaretta, Michele De Donno, Nicola Dragoni
Summary Disbursement registration has always been a cumbersome, opaque, and inefficient process, up to the point that most businesses perform cash‐flow evaluations only on a quarterly basis. We believe that automatic cash‐flow evaluations can actively mitigate these issues. In this paper, we present BitFlow, a blockchain‐based architecture that provides complete cash‐flow transparency and diminishes the probability of undetected frauds through the BitKrone, a non‐volatile cryptocurrency that maps to the Danish Krone ( DKK ). We show that confidentiality can be effectively achieved on a permissionless blockchain using Zero‐Knowledge proofs, ensuring verifiable transfers and automatic evaluations. Furthermore, we discuss several experiments to evaluate our proposal, in particular, the impact that confidential transactions have on the whole system, in terms of responsiveness and from an economical expenditure perspective.