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In a recent paper (Gong et al. Quantum Inf Process 19:3, 2020), a novel ciphertext retrieval scheme based on the Grover algorithm and quantum homomorphic encryption was presented. In this scheme, when the server performs the operation of marking the solution on the user’s encrypted state in the Grover iteration, it needs to remove many gate-errors generated in the homomorphic evaluation of the T gate. And the server could judge this specific solution from the quantum circuit of marking the solution. It makes this scheme unable to achieve the low-cost and secure ciphertext retrieval. Therefore, we improve the Gong et al.’s scheme and propose a secure quantum homomorphic encryption ciphertext retrieval scheme. In our scheme, the trusted third party is introduced to cooperate with the server to execute the Grover algorithm. In each Grover iteration, the trusted third party can quickly mark the solution on the plaintext state, encrypt the marked state, and transmit it to the server. Then the server performs the remaining operations of this Grover iteration on the encrypted state. The trusted third party finally decrypts the iterated state. This cooperative approach ensures that the number of auxiliary qubits required and extra quantum gates executed in our scheme are lower than the Gong et al.’s scheme. By analyzing the security of our scheme, we confirm that the server and the trusted third party will not be informed of this solution. Thus, our scheme realizes the secure ciphertext retrieval with low computational overhead. We utilize IBM’s Qiskit framework to simulate our scheme, and the experimental result shows that our scheme is correct. It is worth noting that the low-cost and secure ciphertext retrieval will play a crucial role in modern information security and privacy protection.

The Internet of Medical Things (IoMT) global market has grown and developed significantly in recent years, and the number of IoMT devices is increasing every year. IoMT systems are now very popular and have become part of our everyday life. However, such systems should be properly protected to preventing unauthorized access to the devices. One of the most popular security methods that additionally relies on real-time communication is Blockchain. Moreover, such a technique can be supported by the Trusted Third Party (TTP), which guarantees data immutability and transparency. The research and industrial community has predicted the proliferation of Blockchain-based IoMT (BIoMT), for providing security, privacy, and effective insurance processing. A connected environment comprises some of the unique features of the IoMT in the form of sensors and devices that capture and measure, recognize and classify, assess risk, notify, make conclusions, and take action. Distributed communication is also unique due to the combination of the fact that the Blockchain cannot be tampered with and the Peer-to-Peer (P2P) technique, especially compared to the traditional cloud-based techniques where the reliance of IoMT systems on the centralized cloud makes it somewhat vulnerable. This paper proposes a Blockchain-based technique oriented on IoMT applications with a focus on maintaining Confidentiality, Integrity, and Availability (the CIA triad) of data communication in the system. The proposed solution is oriented toward trusted and secure real-time communication. The presented method is illustrated by an example of a cloud-based hospital application. Finally, the security aspects of the proposed approach are studied and analyzed in detail.

The large-scale deployment of cloud composite services distributed over heterogeneous environments poses new challenges in terms of security management. In particular, the migration of their resources is facilitated by recent advances in the area of virtualization techniques. This contributes to increase the dynamics of their configuration, and may induce vulnerabilities that could compromise the security of cloud resources, or even of the whole service. In addition, cloud providers may be reluctant to share precise information regarding the configuration of their infrastructures with cloud tenants that build and deploy cloud composite services. This makes the assessment of vulnerabilities difficult to be performed with only a partial view on the overall configuration. We therefore propose in this article an inter-cloud trusted third-party approach, called C3S-TTP, for supporting secure configurations in cloud composite services, more specifically during the migration of their resources. We describe the considered architecture, its main building blocks and their interactions based on an extended version of the TOSCA orchestration language. The trusted third party is capable to perform a precise and exhaustive vulnerability assessment, without requiring the cloud provider and the cloud tenant to share critical configuration information between each other. After designing and formalizing this third party solution, we perform large series of experiments based on a proof-of-concept prototype in order to quantify its benefits and limits.

In this paper, we leverage the properties of the swap test to evaluate the similarity of two qubits and propose a two-party quantum private comparison (QPC) protocol involving a semi-trusted third party (TP). The TP facilitates the comparison between participants without accessing their private information, other than the final comparison results. Our protocol encodes participants’ secret integers directly into the amplitudes of single-photon states and introduces a novel method for secret-to-secret comparison rather than the traditional bit-to-bit comparison, resulting in improved scalability. To ensure security, the encoded single-photon states are concealed using rotation operations. The comparison results are derived through the implementation of the swap test. A simulation on the IBM Quantum Platform demonstrates the protocol’s feasibility, and a security analysis confirms its robustness against potential eavesdropping and participant attacks. Compared with existing QPC protocols that employ bit-to-bit comparison methods, our approach offers improved practicality and scalability. Specifically, it integrates single-photon states, rotation operations, and the swap test as key components for direct secret comparison, facilitating easier implementation with quantum technology.

In this article, proposals for the realization of an infrastructural re-think on the way authentication, authorization and accounting (AAA) services and charging and billing (C&B) services are supplied within the ubiquitous consumer wireless world (UCWW) are set out. Proposals envisage these services being owned and organized by trusted third parties (TTPs) and utilizing new globally standardized protocols and infrastructural entity interfaces. Their implementation will affect a successful realization of the UCWW’s consumer-based techno-business infrastructure, complementing or even replacing the present legacy network-centric, subscriber-based one. The approach enables a loose dynamic, or even casual, consumer-type association between consumers (mobile users) and network/teleservice providers, and it opens the door to multifaceted benefits for consumers, for new network/teleservice providers, and for other new UCWW business entities in addition to the 3P-AAA and 3P-C&B service providers at the heart of this article’s proposals.

Cryptography plays a crucial role in safeguarding data from unauthorized access and unnoticed alterations during transmission. It relies on cryptographic algorithms and keys as fundamental components of secure systems. Across diverse security domains, cryptography is employed to shield sensitive information, from confidential IT data to financial and healthcare records. The foundation of data security in cryptography lies in the sharing of cryptographic keys between parties. This paper explores a key sharing approach involving a trusted third party, as well as the utilization of graph-based properties to establish secure key exchange. By leveraging cryptographic techniques, users can ensure the integrity and confidentiality of their data, immune to malicious breaches. Notably, the method’s effectiveness relies on the graph properties of the Hamiltonian path sequence, establishing robust security into the algorithm. The encryption and decryption procedures within this system exhibit a time complexity of O(n), which scales with data size. It’s important to recognize that the complexity of discovering the Hamiltonian path is further compounded by an increase in data volume.

Location-Based Services (LBS) System is rapidly growing due to radio communication services with wireless mobile devices having a positioning component in it. LBS System offers location-based services by knowing the actual user position. A mobile user uses LBS to access services relevant to their locations. In order to provide Point of Interest (POI), LBS confronts numerous privacy related challenges in three different formats including Non-Trusted Third Party (NTTP), Trusted Third Party (TTP), and Mobile Peer-to-Peer (P2P). The current study emphasized the TTP based LBS system where the Location server does not provide full privacy to mobile users. In TTP based LBS system, a user’s privacy is concerned with personal identity, location information, and time information. In order to accomplish privacy under these concerns, state-of-the-art existing mechanisms have been reviewed. Hence, the aim to provide a promising roadmap to research and development communities for the right selection of privacy approach has achieved by conducting a comparative survey of the TTP based approaches. Leading to these privacy attributes, the current study addressed the privacy challenge by proposing a new privacy protection model named “Improved Dummy Position” (IDP) that protects TIP (Time, Identity, and Position) attributes under TTP LBS System. In order to validate the privacy level, a comparative analysis has been conducted by implementing the proposed IDP model in the simulation tool, Riverbed Modeler academic edition. The different scenarios of changing query transferring rate evaluate the performance of the proposed model. Simulation results demonstrate that our IDP could be considered as a promising model to protect user’s TIP attributes in a TTP based LBS system due to better performance and improved privacy level. Further, the proposed model extensively compared with the existing work.

Co-consumption sharing economy platforms digitally connect strangers for mutually beneficial co-consumption of services, such as ride sharing or home sharing. In addition to efficiency gains, this is particularly relevant for the sustainable use of resources. While digital platforms have become efficient at building trust in third-party providers, co-consumption service experiences require rapport between individuals—an intersubjective fit between a client and a provider that cannot be ensured in advance by guarantees or ratings. Little is known about the role of uncertainty concerning rapport when brokering co-consumption services and how platform design can cater to users’ need for rapport. This study therefore introduces rapport uncertainty as a two-dimensional construct consisting of interaction uncertainty and connection uncertainty and draws on the service literature to derive a research model that captures the role of design features in mitigating rapport uncertainty. Our experimental study reveals that rapport uncertainty is a key determinant of platform use beyond technical and environmental uncertainties and demonstrates how platform design can reduce rapport uncertainty and facilitate transactions in co-consumption environments.

Compared with the traditional system, cloud storage users have no direct control over their data, so users are most concerned about security for their data stored in the cloud. One security requirement is to resolve any threats from semi-trusted key third party managers. The proposed data security for cloud environment with semi-trusted third party (DaSCE) protocol has solved the security threat of key managers to some extent but has not achieved positive results. Based on this, this paper proposes a semi-trusted third-party data security protocol (ADSS), which can effectively remove this security threat by adding time stamp and blind factor to prevent key managers and intermediaries from intercepting and decrypting user data. Moreover, the ADSS protocol is proved to provide indistinguishable security under a chosen ciphertext attack. Finally, the performance evaluation and simulation of the protocol show that the ADSS security is greater than DaSCE, and the amount of time needed is lower than DaSCE.

In recent years, the rapid development of blockchain technology and cryptocurrencies has influenced the financial industry by creating a new crypto-economy. Then, next-generation decentralized applications without involving a trusted third-party have emerged thanks to the appearance of smart contracts, which are computer protocols designed to facilitate, verify, and enforce automatically the negotiation and agreement among multiple untrustworthy parties. Despite the bright side of smart contracts, several concerns continue to undermine their adoption, such as security threats, vulnerabilities, and legal issues. In this paper, we present a comprehensive survey of blockchain-enabled smart contracts from both technical and usage points of view. To do so, we present a taxonomy of existing blockchain-enabled smart contract solutions, categorize the included research papers, and discuss the existing smart contract-based studies. Based on the findings from the survey, we identify a set of challenges and open issues that need to be addressed in future studies. Finally, we identify future trends.