UnLynx: A Decentralized System for Privacy-Conscious Data Sharing

Cloud computing provides a novel computing paradigm for enterprises to store programs and data in the Cloud in a transparent manner, which poses the challenge of security and privacy. In this paper, based on homomorphic cryptography and Zero-Knowledge Proof, we present a novel privacy-preserving scheme for Cloud publish/subscribe service, which achieve efficient privacy-preserving authentication, data integrity, and publish-subscribe confidentiality. The performance evaluation and security analysis demonstrate the practice and validity of the proposed scheme.

Password-based authentication systems are vulnerable to a variety of security risks, such as phishing, credential theft, and user fatigue due to complex password requirements. This paper introduces a novel passwordless authentication framework that leverages advanced cryptographic techniques, including Zero-Knowledge Proofs (ZKP), Secure Multi-Party Computation (SMPC), and Homomorphic Encryption to enhance security, privacy, and user experience. The proposed system eliminates the need for traditional passwords by utilizing biometric data to generate cryptographic keys, ensuring that sensitive information remains secure. The architecture is composed of three primary components: the client device, the authentication server, and the key management system (KMS). The client device captures biometric data and transforms it into cryptographic keys using SMPC, while the server verifies the authentication using ZKP and establishes secure communication channels via Diffie-Hellman key exchange. The KMS handles key generation, storage, and rotation to ensure secure communication. Evaluation results show that the system is highly resistant to common attack vectors such as replay and man-in-the-middle attacks, with a 0% attack success rate. Performance analysis reveals an average authentication time of 180 ms, which is 10% faster than WebAuthn.

In international nuclear safeguards, the International Atomic Energy Agency (IAEA) is tasked with inspecting and verifying nuclear facilities and their activities. Data analytics and machine learning to support inspections require large amounts of data that nuclear facility operators may consider proprietary or sensitive, so the IAEA may not have full access. Allowing computation over private data without compromising its security therefore has value for safeguards inspections and analysis. Privacy-preserving machine learning (PPML) consists of security-focused techniques that allow data analytics and machine learning algorithms to run on sensitive data without revealing it. This includes ideas like homomorphic encryption (HE), secure multiparty computation (SMPC), and secure enclaves. HE allows algorithms and mathematical operations to be conducted directly on the encrypted data instead of first decrypting it. With SMPC, multiple entities collaboratively compute over distributed data such that no party is able to directly view any others’ original data. Secure enclaves allow computation to take place in a separate and heavily blocked-off section of a CPU. Techniques like these allow for several potential use cases in which the security of data is essential. With SMPC, machine learning models can be trained over the input data from multiple entities, resulting in a model that all users can benefit from without leaking the input data from any particular entity. With SMPC or a zero-knowledge proof (ZKP), an algorithm returning some single answer or truth value can be run on someone else’s data without ever needing to see that data, potentially allowing for verification or proof of some underlying question. HE can allow for outsourcing computation on data to a hostile or untrusted environment. Although most of the research in this field resides within the health and financial domains, tools from PPML may have similar applications in nuclear safeguards. Allowing the IAEA to compute over proprietary information, such as process models and raw sensor data using PPML techniques, provides the baseline for running complex analytics without needing direct unencrypted access to the underlying data, maintaining its privacy. Important limitations to consider for these techniques include the efficiency and level of security required. The security of HE and SMPC come at the cost of speed—the significant amount of overhead means that algorithms implemented in these protocols and encryption schemes are slower than when run on plaintext. Additionally, several important parameters determine what techniques or protocols are used based on the security requirements. SMPC protocols may need to be selected for resistance against a party that attempts to deviate from the protocol to distort the result or gain access to additional information, and a protocol secure against these attacks may further increase the overhead of the algorithm.

This paper discusses the decision problem concerning security for such cryptographic protocols as the cryptographic key distribution protocols and the digital signature protocols. A cryptographic protocol and its utilization environment are considered secure if an opponent cannot know the secret message or forge a signature successfully by wiretapping or communication function is secure. This paper presents a sufficient condition under which the security problem is decidable. Dolev et al. also investigated the decision problem of the security, but they discussed only the simple case where the cryptographic key is not the object of manipulation (i.e., key generation and distribution are not included in the protocol), and a decision method is presented in which the decision can be made in a polynomial time. By contrast, this paper discusses the problem including the case where the cryptographic key can be an object of manipulation. The key delivery protocol by Ehrsam et al. and the digital signature protocol by Needham et al. satisfy the sufficient condition for the decidability given in this paper. Under the sufficient condition given in this paper, the security can again be decided in a polynomial time.

Zero Knowledge Proofs (ZKPs) have emerged as transformative cryptographic primitives, enabling a wide variety of modern privacy-preserving applications across various domains. This paper presents substantial advancements in contemporary ZKPs, exploring the latest trends in ZKP schemes, novel applications, and scalable ZKP-based systems. We provide an in-depth analysis of state-of-the-art ZKP structures, including zk-SNARKs, zk-STARKs, and the more recent zk-Rollup technologies. We examine the unique properties and use cases of these techniques, highlighting their potential to enhance privacy, security, and trust in digital systems. Our research into zk-Rollups demonstrates significant improvements in transaction throughput and gas efficiency, paving the way for the extensive deployment of modern privacy-preserving solutions. Furthermore, we showcase several innovative applications of ZKPs, such as privacy-preserving decentralized finance (DeFi) protocols, anonymous credentials, and secure multi-party computation. These use cases illustrate the transformative potential of advanced ZKPs to improve privacy and security across a range of digital domains. To foster wider adoption of modern ZKPs, we have developed and opensourced a collection of advanced tools and libraries that simplify the implementation of ZKP-based solutions. We also offer practical guidance and best practices for developers and researchers working in this field, aiming to accelerate the development and real-world impact of modern zero-knowledge proof systems.

: Authentication is deemed to be a critical function in the operation of tactical wireless ad hoc networks. The dynamic nature and unpredictability of these self - organizing networks requires that new security protocols be deployed that allow users to efficiently gain access to network resources without the burden of a centralized security infrastructure. Authentication protocols based on Zero - Knowledge Proof (ZKP) of identity schemes provide a means for establishing mutual trust between network entities. While many papers have looked at the virtues of ZKP - based authentication protocols from an academic perspective, little work has been carried out to actually deploy and test the protocols in fielded wireless networks. In this paper we present lessons - learned regarding the installation of ZKP - based authentication protocol on processing hardware designed for deployment on AFRL's small unmanned aerial vehicle (UAV) test bed.

Secure computation protocols inherently involve multiple rounds of interaction among the parties where, typically a party has to keep a state about what has happened in the protocol so far and then wait for the other party to respond. We study if this is inherent. In particular, we study the possibility of designing cryptographic protocols where the parties can be completely stateless and compute the outgoing message by applying a single fixed function to the incoming message (independent of any state). The problem of designing stateless secure computation protocols can be reduced to the problem of designing protocols satisfying the notion of resettable computation introduced by Canetti, Goldreich, Goldwasser and Micali (FOCS'01) and widely studied thereafter. The current start of art in resettable computation allows for construction of protocols which provide security only when a single predetermined party is resettable [15]. An exception is for the case of the zero-knowledge functionality for which a protocol in which both parties are resettable was recently obtained by Deng, Goyal and Sahai (FOCS'09). The fundamental question left open in this sequence of works is, whether fully-resettable computation is possible, when: 1) An adversary can corrupt any number of parties, and 2) The adversary can reset any party to its original state during the execution of the protocol and can restart the protocol. In this paper, we resolve the above problem by constructing secure protocols realizing any efficiently computable multi-party functionality in the plain model under standard cryptographic assumptions. First, we construct a Fully-Resettable Simulation Sound Zero-Knowledge (ss-rs-rZK) protocol. Next, based on these ss-rs-rZK protocols, we show how to compile any semi-honest secure protocol into a protocol secure against fully resetting adversaries. Next, we study a seemingly unrelated open question: "Does there exist a functionality which, in the concurrent setting, is impossible to securely realize using BB simulation but can be realized using NBB simulation?". We resolve the above question in the affirmative by giving an example of such a (reactive) functionality. Somewhat surprisingly, this is done by making a connection to the existence of a fully resettable simulation sound zero-knowledge protocol.

Visual cryptography is a cryptographic method that encrypts visual facts and the information decrypted appears as an original visual image. Here, the confidential data is shared by dividing the visual details into multiple shares such that the encryption and the decryption are performed for reconstructing the original image back by stacking the splitted shares. However, the data sharing process lacks adequate security protection. To overcome the issues, this paper presents a robust visual cryptography-based data sharing scheme, named Competitive Swarm Improved Invasive Weed Optimization (CSIIWO) for sharing multiple data. Initially, the grayscale input image is shared between several parties, such that the shared image is encrypted and decrypted for retrieving the original image back. However, the cryptographic key generation is done using the devised CSIIWO algorithm such that the cryptographic keys are generated for the data sharing process to maintain confidentiality among multiple parties. Moreover, the devised method achieved the maximum Peak signal-to-noise ratio (PSNR) of 40.749 dB, minimum conditional privacy loss of 0.508, and maximum entropy of 7.987, respectively using Lena image. Furthermore, the proposed scheme can protect the multiple data sharing information and has numerous advantages compared with the previous mechanisms.

The integration of Zero-Trust Architecture (ZTA) and Blockchain-based Security Models in IoT-driven industrial power electronics systems has emerged as a transformative approach to mitigating cyber threats and ensuring robust access control. Traditional security mechanisms, which rely on perimeter-based defenses, are increasingly ineffective against advanced persistent threats (APTs), insider attacks, and lateral movement techniques within industrial IoT (IIoT) environments. Zero-Trust security enforces continuous verification, least-privilege access, and micro-segmentation, ensuring that no device or user was inherently trusted. Implementing ZTA in resource-constrained IoT ecosystems presents significant challenges related to computational overhead, authentication latency, and secure data transmission. To address these limitations, blockchain technology enhances decentralized identity management, immutable access logs, and tamper-resistant security frameworks, fortifying Zero-Trust-based access control. Privacy-preserving cryptographic techniques, including zero-knowledge proofs (ZKPs) and homomorphic encryption, safeguard sensitive industrial data while maintaining compliance with evolving regulatory frameworks. AI-driven anomaly detection models reinforce continuous authentication and behavior-based threat monitoring, enabling proactive defense mechanisms against zero-day exploits and sophisticated cyber intrusions. This chapter presents a comprehensive analysis of Zero-Trust implementation models for IIoT systems, highlighting the role of secure communication protocols, distributed ledger-based identity verification, and adaptive security automation. The integration of blockchain-enabled access control and AI-powered real-time security analytics ensures a resilient security posture for industrial power electronics networks, mitigating risks associated with unauthorized access, data breaches, and operational disruptions. The proposed framework enhances scalability, privacy, and computational efficiency, paving the way for next-generation cybersecure industrial ecosystems.

WANET is a network built in an ad hoc network where various connecting devices and moving wireless nodes make connection with the exchange valuable information and wireless medium to one another. As the size of the wireless networks and internet architectures are increasing, there is an exponential demand for data processing and sharing resources in the WANETs. Most of the traditional node authentication models in WANET’s require high computational memory and resource constraints for data security and node authentication. In order to overcome these problems in the traditional models, a novel non-linear integrity-based intrusion detection models is designed and implemented in WANETs. In this work, a hybrid security protocol is designed and developed for the node-to-node communication system. In the proposed security protocol, a hybrid integrity approach and encryption framework is implemented on N2N communication process. Experimental results show that the present security protocol has better improvement on different metrics over traditional security approaches.

SummaryCloud of Things (CoT) is a novel concept driven by the synergy of the Internet of Things (IoT) and cloud computing paradigm. The CoT concept has expedited the development of smart services resulting in the proliferation of their real world deployments. However, new research challenges arise because of the transition of research‐driven and proof‐of‐concept solutions to commercial offerings, which need to provide secure, energy‐efficient, and reliable services. An open research issue in the CoT is to provide a satisfactory level of security between various IoT devices and the cloud. Existing solutions for secure CoT communication typically use devices with pre‐loaded and pre‐configured parameters, which define a static setup for secure communication. In contrast to existing pre‐configured solutions, we present an adaptable model for secure communication in CoT environments. The model defines six secure communication operations to enable CoT entities to autonomously and dynamically agree on the security protocol and cryptographic keys used for communication. Further on, we focus on device agreement and present an original solution, which uses the Agile Cryptographic Agreement Protocol in the context of CoT. We verify our solution by a prototype implementation of CoT device agreement based on required security level, which takes into account the capabilities of communicating devices. Our experimental evaluation compares the average processing times of the proposed secure communication operations demonstrating the viability of the proposed solution in real‐world deployments. Copyright © 2016 John Wiley & Sons, Ltd.

Ring Confidential Transaction (RingCT) protocols are widely used in cryptocurrencies to protect user privacy. Consequently, a corresponding digital signature scheme, such as a ring signature scheme that hides the signers’ identities, is required. Accordingly, the security of a RingCT protocol depends on the confidentiality of the secret signing keys of the underlying ring signature scheme. However, existing solutions like hardware wallets, Trusted Execution Environments (TEEs), and threshold signature schemes have limitations such as specified expensive hardware, targeting attacks at CPUs on insufficiently secure hardware, and overheads caused by multiple parties. On the contrary, program obfuscation for signature schemes offers advantages over these existing approaches. Concretely, we propose a novel obfuscator that secures the secret keys of the concise linkable spontaneous anonymous group (CLSAG) signature scheme, which is the latest ring signature scheme used in Monero’s RingCT protocol. To achieve enhanced security, the proposed obfuscator leverages Paillier homomorphic encryption to transform secret keys into an obfuscated form resistant to attacks. The security of the proposed obfuscator has been formally proved. Computational efficiency has been both theoretically analyzed and experimentally evaluated with positive results on various testing platforms.

<sec>The absolute security of quantum communication protocols relies on a critical premise: all participating parties are legitimate users. Ensuring the legitimacy of participant identities is paramount in complex real-world communication environments. Quantum identity authentication (QIA), in which fundamental principles of quantum mechanics are used to achieve unilateral or mutual authentication between communicating parties, constitutes an indispensable core component for building a comprehensive quantum secure communication system. It holds significant research value in the field of quantum communication.</sec><sec>This review employs a comparative classification method to systematically outline the research trajectory of QIA protocols. By categorizing protocols based on the required quantum resources and the types of quantum protocols employed, the advantages and disadvantages of various categories are analyzed in terms of efficiency, security, and practicality. Single-photon protocols require low resources, and they are easy to implement, and compatible with existing optical components, but require high-efficiency single-photon detectors and exhibit weak noise resistance. Entangled-state protocols offer high security and strong resistance to eavesdropping, particularly suitable for long-distance or multi-party authentication. However, they greatly depend on the preparation and maintenance of high-precision, stable multi-particle entanglement sources, resulting in high experimental complexity. Continuous-variable (CV) protocols achieve high transmission efficiency in short-distance metropolitan area networks and are compatible with classical optical communication equipment, making experiments relatively straightforward. Yet, they require high-precision modulation technology and are sensitive to channel loss. Hybrid protocols aim to balance resource efficiency and security while reducing reliance on a single quantum source, but their design is complex and may introduce new attack vectors. Quantum key distribution (QKD) framework protocols embed identity authentication in the key distribution process, making them suitable for scenarios requiring long-term secure key distribution, although they often depend on pre-shared keys or trusted third parties. Quantum secure direct communication (QSDC) framework protocols integrate authentication with secure direct information transmission, offering high efficiency for real-time communication, but requiring high channel quality. Measurement-device-independent QSDC (MDI-QSDC) represents a key development direction that can resist attacks on measurement devices. Quantum teleportation (QT) framework protocols achieves cross-node authentication and unconditional security, making it suitable for quantum relay networks despite its high experimental complexity. The entanglement swapping framework protocol can resist conspiracy attacks and is suitable for multi-party joint scenarios, but it consumes a lot of resources and relies on trusted third party. Ping-pong protocol framework supports dynamic key updates and exhibits strong resistance to eavesdropping, making it suitable for temporary authentication on mobile terminals, although it typically only supports unilateral authentication and requires a bidirectional channel.</sec><sec>Subsequently, this review details the latest QIA protocols of our research group, including a multi-party synchronous identity authentication protocol based on Greenberger-Horne-Zeilinger (GHZ) states, and a tripartite QSDC protocol with identity authentication capabilities utilizing polarization-spatial super-coding. The GHZ-based multi-party synchronous authentication protocol leverages the strong correlations inherent in GHZ states to achieve simultaneous authentication among multiple parties. Through a carefully designed two-round decoy-state detection mechanism, it effectively resists both external eavesdropping and internal attacks originating from authenticated users, thereby enhancing the efficiency and security of identity management in large-scale quantum networks. The core innovation of the polarization-spatial super-coding tripartite QSDC protocol lies in its deep integration of the authentication process with information transmission by utilizing the spatial degrees of freedom of single photons. This design accomplishes the identity verification of two senders and the transmission of secret information within a single protocol run, ensuring end-to-end security through a three-stage security check. This “authentication-as-communication” paradigm significantly improves the overall efficiency and practicality of the protocol. Its successful implementation also relies on advancements in quantum memory technology.</sec><sec>Finally, the review outlines future research directions for quantum identity authentication and explores its potential applications in quantum communication. The QIA research needs to focus on reducing resource dependency, exploring more efficient protocol designs, further enhancing protocol integration and robustness, prioritizing the development of protocols adaptable to real-world environments, and actively investigating integration with novel scenarios. This comprehensive review aims to provide theoretical research foundations and technical support for the practical development of future quantum identity authentication.</sec>

DRBFT: Delegated randomization Byzantine fault tolerance consensus protocol for blockchains

People are worried about the lack of security guarantees in classical IEEE 802.11 security protocols, especially since wireless networks are becoming more ubiquitous across public spaces, private facilities, and mission-critical application revisions, potentially vulnerable to quantum computer threats. Current encryption algorithms, such as WEP, WPA, and/or WPA2, are designed based on computational hardness assumptions, making them more insecure with hard quantum algorithms that break current key exchange mechanisms. We develop a quantum-assisted security framework for the IEEE 802.11 architecture, integrating the SARG04-based Quantum Key Distribution (QKD) protocol and an innovative Quantum Message Integrity Code (Q-MIC). The second framework introduces modifications to the 4-Way Handshake, enabling the secure exchange and authentication of encryption keys while maintaining QKD backward compatibility with non-quantum-capable devices. Experimental analysis indicates a tremendous improvement compared to other protocols (including WPA2 and the hybrid WPA3 + Post-Quantum Cryptography (PQC) framework) with an accuracy of 94.1 percent, a minimal reduction of RMSE at 2.34, and an increased capability against replay and man-in-the-middle attacks. The proposed system satisfies the specified need; it is not only scalable and a future-proof design but can also be adopted in areas where security is enforced, such as the defence, banking, and governmental cross-communication sectors. The framework also takes advantage of quantum mechanics by using it to perform key exchange, thereby eradicating the vulnerability of standard classical protocols and providing a strong basis for next-generation wireless security. The present study is theoretical, but the estimations are made with the help of a simulation and comparative analysis, not a new dataset experiment.