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8,503 results · page 166 of 355
Yongming Fan, Yuquan Xu, Christina Garman
No abstract is available for this record.
Innocent Pangapanga‐Phiri, Hambulo Ngoma, Christian Thierfelder
Abstract Smallholder farming systems need climate-proofing and sustainable intensification practices such as conservation agriculture (CA), are promising options. However, there is a general perception that the adoption of CA systems in southern Africa is low. Sentinel sites, where CA has been promoted for a long time, offer forward-looking new insights. This paper, thus, takes a deep dive at Nkhotakota district of Malawi to understand what could have led to the success of CA promotion and subsequent perceived high adoption. We use survey data from 620 farmers, with 298 farmers sampled from treatment areas – known to have had contact with host farmers and 320 from a control group. Overall, 31% of the farmers in both groups adopted full CA over at least a 2-year period. We also find that about 57% of farmers in the treatment area adopted full CA and only 7% of farmers in the control areas. This highlights that longer-term CA promotion with dedicated extension support can enhance the uptake of CA practices. In essence, this paper offers a different perspective to the current narrative that CA systems are too complex and knowledge intensive to be adopted despite its long-term promotion and significant investments. However, there are some nuances: sustained adoption even in sentinel sites is neither 100% nor persistent over the long term. We find an appreciable adoption decay, showing large declines from highs of 57 and 7% in adoption for at least 2 years for treatment and control, respectively, to 12% in the treatment group and practically zero in the control when we condition full CA adoption to at least 7 years. This means that fewer farmers adopted CA for a longer period and suggests some dis-adoption over time even in sentinel sites. The key adoption enablers in the sentinel sites include the availability of training, dedicated longer-term extension support coupled with farmer experiential learning through demonstration plots managed by host farmers. Based on our findings, there is need to consistently promote CA using farmer-centric approaches that include peer-to-peer learning over long periods. This allows farmers time to experiment with different CA options, enable behavioral and lasting change. At policy level, there is need to build and strengthen farmer groups to facilitate easier access to inputs like leguminous crop seeds for farmers practicing CA and to offer market-smart incentives to induce initial adoption in the short term to facilitate sustained adoption.
Cheng Huang, Xuemin Shen
No abstract is available for this record.
Zeng Huang, Ming‐Tian Zhang, Tengfei Liu, Anjia Yang
Federated learning is an important distributed model training technique in Internet of Things (IoT), in which participant selection is a key component that plays a role in improving training efficiency and model accuracy. This module enables a central server to select a subset of participants to perform model training based on data and device information. By doing so, selected participants are rewarded and actively perform model training, while participants that are detrimental to training efficiency and model accuracy are excluded. However, in practice, participants may suspect that the central server may have miscalculated and thus not made the selection honestly. This lack of trustworthiness problem, which can demotivate participants, has received little attention. Another problem that has received little attention is the leakage of participants’ private information during the selection process. We will therefore propose a federated learning framework with auditable participant selection. It supports smart contracts in selecting a set of suitable participants based on their training loss without compromising the privacy. Considering the possibility of malicious campaigning and impersonation of participants, the framework employs commitment schemes and zero-knowledge proofs to counteract these malicious behaviors. Finally, we analyze the security of the framework and conduct a series of experiments to demonstrate that the framework can effectively improve the efficiency of federated learning.
Ezekiel Ologunde
No abstract is available for this record.
Miaoyu Li, Haoxin Li, Zilin Du, Boyang Li
No abstract is available for this record.
Rui Cao, Jing Jiang
No abstract is available for this record.
Hideaki Miyaji, Yuntao Wang, Atsuko Miyaji
Commitment schemes are cryptographic schemes that can be applied to zero-knowledge proof construction and blockchain construction. Recently, lattice-based cryptography has been intensively investigated due to the promising potential in quantum cryptography. Accordingly, commitment schemes based on lattice assumptions have been studied for practical applications. Notably, applications often require committing an arbitrary message with low communication costs, so commitment schemes must be satisfied with fewer length restrictions and fewer extensions to the messages. Several studies have been conducted to achieve the problem, including the study published by Baum et al. in 2018. However, the scheme in question still utilizes the message domain for extraneous purposes. We design a length-extension-free commitment scheme ComMWMin which the length of the message string is large relative to the length of the commitment string, improving on the commitment scheme of Baum et al. Furthermore, we prove that the hiding and binding properties of ComMWMare based on the hardness of the decisional search knapsack problem and extended search knapsack problems, respectively. Finally, we evaluate the computation costs of generating commitment value between ours and Baum et al.’s commitment scheme.
Yuncong Zhang, Shi-Feng Sun, Dawu Gu
No abstract is available for this record.
Julia Kästner, Ky Nguyen, Michael Reichle
No abstract is available for this record.
Xiaotong Li, Hao Wang, Jiyang Chen, Shikuan Li · 6 authors
No abstract is available for this record.
Yong Zhou, Hong Lei, Zijian Bao
Charity donations are a critical mechanism for social resource distribution. However, traditional donation systems, typically centralized, are prone to issues such as data redundancy, vulnerability to single-point failures, and a deficiency in transparency and traceability. Although blockchain-based donation programs have emerged to address trust issues inherent in centralized models, they often neglect critical security concerns like privacy protection and identity authentication. This paper introduces Eisdspa, a blockchain-based donation system designed to offer identity authentication, auditability, and privacy protection. Specifically, we introduce an identity credential system that facilitates anonymous donations, shielding the identities of both donors and donees through the use of BBS+ signatures and zero-knowledge proofs of knowledge (ZKPoKs). Additionally, we ensure the integrity of goods donations by offering robust auditability and protecting user privacy with Pedersen commitments and ZKPoKs. We formally define the privacy aspects of Eisdspa and conduct a security analysis of the system under the random oracle model. A prototype implementation of the scheme, along with a comparative analysis with existing solutions, highlights the benefits of Eisdspa. Moreover, we assess the computational efficiency of Eisdspa, with experimental results indicating its high performance in computational overhead.
Yiming Li, Shengli Liu
No abstract is available for this record.
Fan Long, Jianfeng Guan, Kexian Liu, Pengcheng Wang
No abstract is available for this record.
Xiao Yang, Chengru Zhang, Haiyang Xue, Man Ho Au
A Verifiably Encrypted Signature (VES) scheme encrypts a digital signature in a way that allows the public to verify the validity of the encrypted signature. Recently, several practical VES schemes for ECDSA have been proposed to enable escrowed transactions with cryptocurrencies. However, these schemes are inefficient in terms of both communication and computation, or require a large lookup table. In this paper, we present two efficient VES schemes for ECDSA that improve upon previous work. The first scheme is based on Castagnos-Laguillaumie (CL) encryption, while the second is based on modified Joye-Libert (JL) encryption. Our benchmark shows that our schemes outperform existing constructions by a factor of at least 2 in both computation and communication. Additionally, our solution does not rely on any lookup table. We demonstrate that these schemes can also be generalized to design VES for Schnorr signature scheme and EdDSA. The main technical contribution of this paper, which is of independent interest, is a zero-knowledge proof for the equality of the discrete log of an elliptic-curve point and that of a JL ciphertext. Importantly, the security of our proof does not rely on any non-standard assumptions.
T. O. Horelikova, С. В. Чопоров
Blockchain technology refers to a chain of blocks constructed according to certain rules, where each block contains information about its own hash sum and the hash sum of the previous block. This organization of records in storing information allows preventing unauthorized alterations, as any change in data in any of the blocks requires changing the hash sums of the entire data chain. Among the advantages of information protection methods based on blockchain technology are security, decentralization, traceability, immutability, automation, and interaction. Blockchain technology enables a secure and interference-resistant method of data storage and transmission, as data is stored in blocks linked together in a chain. This complicates unauthorized users’ attempts to alter data or access it without permission. This article presents the results of research on the use of blockchain technology methods to address the issue of protecting information from tampering. The research conducted in this study analyzes various aspects of blockchain technology, including data structures, programs, legal implications, supply chain management, digital signatures, public key cryptography, and zero-knowledge proofs. Methods such as hashing, digital signature operations, public key cryptography, and zero-knowledge proofs are used to protect data in blockchain. These methods ensure the security, confidentiality, and efficiency of data processing, but the performance of their implementations depends on the selected software and hardware. Additionally, these mentioned methods have their specific vulnerabilities to cyberattacks.
Marek Sefranek
No abstract is available for this record.
Tomer Ashur, Thomas Buschman, Mohammad Mahzoun
No abstract is available for this record.
Vladimir Popov, Mikhail Krupin, Andrew Gross, Georgi Koreli
New advancements in zero-knowledge proof construction, including improvements in user experience, have made blockchain-based privacy applications more accessible than ever.However, additional measures are required to balance the needs of regulators, the basic privacy rights of users, and the constant threat of bad actors.To address these issues, privacy protocols can introduce features designed to increase transparency, encourage compliance, and prevent illicit use.In this paper, current privacy-preserving methods (privacy pools) are explained along with compliance measures designed to prevent illicit usage.These measures are divided into three broad categories: general restrictions, such as transaction limits, deposit quarantine, and geoblocking; selective disclosure, such as privacy-preserving KYC, proof of innocence, and opt-in reporting; and threat identification and prevention, including AML wallet screening.Each of these methods are described in detail along with examples of three privacypreserving protocols (Hinkal, RAILGUN, and zkBob) which utilize varying combinations of these methodologies to achieve privacy informed by selfregulatory compliance.
Mutiullah Shaikh, Sundas Munir, Uffe Kock Wiil, Amina Shaikh
No abstract is available for this record.
Cheng Huang, Xuemin Shen
No abstract is available for this record.
Fang Li, Xiaofen Wang, Tao Chen, Lin Li · 5 authors
No abstract is available for this record.
Caiqun Shi, Qinlong Huang, Rui Jian, Genghui Chi
The quality of medical services is improved by sharing electronic medical records (EMRs) across multiple medical institutions via cloud edge. However, EMRs contain private information about patients, and cloud servers are untrustworthy, thus they cannot be shared arbitrarily among senders and receivers. Access control encryption (ACE) is a preferred technique that produces encrypted EMRs and then restricts the capabilities of both senders and receivers to enforce the EMR flow via sanitizers. However, existing cross-domain ACE schemes employ a single sender authority to issue encryption keys for senders, which suffers from single point of failure and encryption key escrow that the sender authority can public EMRs arbitrarily. Moreover, they only support coarse-grained access structures such as AND gates, which is not suitable for flexible EMR sharing among medical institutions. To this end, we propose a cross-domain inner-product ACE (CD-IPACE) scheme that features decentralized encryption key generation and fine-grained access structures. Specifically, we construct CD-IPACE from inner-product encryption, threshold structure-preserving signature instantiated with a distributed key generation protocol, and non-interactive zero-knowledge proof, which prevents individual sender authorities from sending ciphertexts, and also protects both data and receiver privacy. Then, we design a secure EMR flow system in cloud edge named ESFlow based on CD-IPACE, which employs edge nodes as sanitizers to check encrypted EMRs and discard illegal ones. Finally, we demonstrate the security and practicality of ESFlow via formal security analysis and extensive experiments.
Le Gao, Junzhe Zhang, Jiaxin Yu, Yin Tang · 5 authors
<abstract><p>The rapid development of blockchain transactions highlights the importance of privacy protection (including anonymity and confidentiality) and underscores the necessity for auditability. Some schemes, such as PGC and Miniledger, support privacy protection and auditability. However, they only offer incomplete privacy protection (i.e., supporting anonymity or confidentiality exclusively). In response to these issues, we propose a scheme that achieves partial anonymity, confidentiality, auditability, and traceability. By integrating a variant of Pedersen commitments and randomizable signatures, we achieve partial anonymity for users and the auditability of transactions, thereby protecting user privacy under audit conditions. Based on the twisted ElGamal encryption algorithm and specially constructed zero-knowledge proofs, we achieve confidentiality of transaction amounts under legal and regulatory conditions. System test results indicate that this scheme effectively meets the above requirements. The feasibility of this scheme is confirmed through system testing, comparative analysis, and security analysis.</p></abstract>