The Internet of Medical Things (IoMT), which integrates medical sensors with the Internet of Things, is helpful for providing remote diagnosis and real-time decision making. Massive data collected by medical and healthcare monitoring sensors in the IoMT involves sensitive patient information. It brings some security challenges to validate the legitimacy of participating entities and protect patient data privacy. A certificateless signcryption (CLSC) scheme combines encryption and signature that can offer authenticity, confidentiality, and unforgeability, providing a viable solution to the data privacy issue of the IoMT. However, existing CLSC schemes fail to meet confidentiality or unforgeability, or require expensive computation overhead to perform pairing operations. This article first presents a new CLSC scheme for secure data transmission and better smart services in IoMT, which replaces the signature part with the Schnorr signature. We then give a thorough security proof under the random oracle model. Besides, we elaborately evaluate the performance and security of some existing solutions with our solution. Finally, the experiment results indicate that our solution can achieve a better balance between security and performance than some existing schemes. Therefore, in terms of feasibility, our scheme is more suitable for the IoMT scenario. 

A Secure Certificateless Signcryption Scheme Without Pairing for Internet of Medical Things

The access frequency pattern leakage reveals sensitive information over encrypted cloud data, such as query inclinations and interests. Even worse, adversaries can infer the content of storage with the help of auxiliary knowledge. It jeopardizes the mutual trust between the client users and the cloud platform as reported in many cases. In this paper, we study the threats model in which adversaries know both the exact in-memory flow of accessed blocks and the processing boundary of each request. Under these settings, he can precisely observe the access frequency patterns in both aggregated and independent perspectives over queries. We then propose the ReFlat module as a counter solution through the K-duplication obfuscation mechanism. ReFlat securely runs inside the hardware enclave provided by Intel SGX and requires no modifications on query processors. The K-duplication mechanism is further optimized with two working functions to practically deal with point and range queries. Comparing with the state-of-the-art schemes using the similar idea, that is, fake query injection, ReFlat eliminates the security risk of involving intermediate proxy and achieves higher robustness under the proposed threat model. We exhibit comparative experiment results showing that ReFlat exceeds existing schemes providing equal security level in multiple system performance metrics. 

ReFlat: A Robust Access Pattern Hiding Solution for General Cloud Query Processing Based on K-isomorphism and Hardware Enclave

Currently, the development of advanced systems in the healthcare industry involves in introducing new technical methods and made a big contribution in saving a person's life rather than the practice of traditional medical methods. Wireless body area network (WBAN) plays a major and vital in developing modern healthcare system. In modern days the healthcare information of patient provided by a medical practitioner get stores in the digital network sites and involves in the trouble of cyber threats and various attacks that may lead to leakage of confidential information of patient in unauthorized sites and sell the medical data illegally. In order to prevent this cause, the proposed system focus on integrity and confidentiality of communication between patient and medical practitioner. The WBAN sensors that are placed in the patient body sends the parameters of the body's state to the medical server and get checked by medical partitioner. Mutual authentication and session key exchange protocol involves securing the integrity, confidentiality of information transferring in between patient and medical practitioner. The proposed system can resist several cyber-attacks and reduced system costs.

A Secure Authenticated Message Transfer in Healthcare Application

A lack of trust in the providers is still a major barrier to cloud computing adoption – especially when sensitive data is involved. While current privacy-enhancing technologies, such as homomorphic encryption, can increase security, they come with a considerable performance overhead. As an alternative Trusted Executing Environment (TEE) provides trust guarantees for code execution in the cloud similar to transport layer security for data transport or advanced encryption standard algorithms for data storage. Cloud infrastructure providers like Amazon, Google, and Microsoft introduced TEEs as part of their infrastructure offerings. This review will shed light on the different technological options of TEEs, as well as give insight into organizational issues regarding their usage.

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Trusted Execution Environments: Applications and Organizational Challenges

This article proposes private intersection weighted sum (PIWS), a scalable, fair, and privacy-preserving intersection weighted sum protocol and applies it to voting scenarios. The PIWS protocol can privately calculate the intersection of identity index sets maintained by each participant and can privately calculate the weighted sum of the data associated with the identity indexes of the intersection set. After the execution of the protocol, both parties can only know the weighted sum, but not any additional information, such as any identity index or associated data of the other party. The PIWS protocol is very suitable for the privacy-preserving weighted voting scenarios and has three novel characteristics. First, it does not require as many semitrusted tally clerks as other protocols, which greatly reduces the deployment, communication, and calculation costs involved. It only requires the distributed deployment of voting servers and weight servers that are honest but curious. This is consistent with the deployment framework of the future big data application backgrounds. Second, perfect privacy protection and ballot secrecy are achieved. That is, the voting terminal or polling station provides encryption services for ballots immediately after each ballot is cast. All voting information is then expressed in ciphertext throughout the weighting and counting processes, until the final result of the weighted vote is passed to the voting server in the ciphertext. After decryption, the voting server only knows the results of the voting and it has no knowledge of the content or preference of the ballots, the privacy of the voters, or even the process of counting the votes. This design avoids the disclosure of voter privacy and ballot information, and the ciphertext form also prevents malicious users from cheating or tampering with voter or ballot information during the counting process. To better explain the security of our protocol, we present the provable security of the protocol under the honest-but-curious model and show the formal verification obtained using the Tamarin prover software. Third, our protocol not only achieves the function of an optional weighted voting protocol but also is relatively lightweight and efficient. The efficiency analysis results of the deployed voting system in terms of communication, storage, and calculation show that the protocol meets the requirements applicable to real-world applications. In summary, PIWS is superior to existing voting protocols in terms of function, security, and efficiency, and can be harmoniously applied to model updating of federated learning, consensus building of blockchain systems, or decision-making in artificial intelligence.

PIWS: Private Intersection Weighted Sum Protocol for Privacy-Preserving Score-Based Voting With Perfect Ballot Secrecy

For users who rely heavily on social networks for entertaining or making friends, sensitive information such as ages, incomes and addresses will be stored in a database without protection. While many companies try their best to protect user privacy, data breaches still happen, resulting in the loss of millions or billions of dollars and the faith of their customers. Therefore, we propose a solution that guarantees the confidentiality and integrity of information while preserving the ability to perform matching over encrypted values. Our solution is built on homomorphic encryption with secure hardware enclaves such as Intel SGX. Our solution resolves challenges such as performing user profile matching on encrypted values without revealing any information to anyone. With the help of multiple servers, user privacy can be protected as long as at least one server is honest and the guarantee of secure hardware makes the secret unlikely to be revealed. Furthermore, a prototype of our system is implemented to measure its performance. The performance analysis and security analysis show the feasibility of our proposed protocols.

SGX-based Users Matching with Privacy Protection

A distributed networked system for secure publicly verifiable self-tallying online voting

The sharing of energy usage data in smart grids is becoming increasingly popular because it not only allows different entities to access fine-grained energy consumption data but also improves the effectiveness of smart grid technologies. How to ensure both verifiability and privacy of the shared data is a vital issue. Most existing privacy-preserving authentication schemes greatly hinder the flexibility of sharing data among multiple parties due to vulnerability and inefficiency reasons. The customer-centric energy usage data management framework based on redactable signature (RS) technology can be seen as an effective solution. It offers customers the flexibility to remove parts of privacy-sensitive data depending on different data usage demands, and ensures data verifiability for third party service providers. However, existing RS schemes are computationally inefficient for constrained devices such as smart meters. Besides, it is said that quantum computers are expected to break all traditional public-key primitives. In this regard, almost all existing RS schemes are vulnerable to quantum attacks. To address the above concerns, in this work, we propose a hash-based RS scheme HRSS based on a variant of the Goldreich-Goldwasser-Micali tree, a length-doubling pseudorandom generator, and an underlying SPHINCS $$^+$$ framework. Our HRSS is the first quantum-safe RS scheme, where the security depends only on the security of underlying hash functions. We instantiate and evaluate the performance of our design. Theoretical and experimental comparisons with recent works show that HRSS is practical for smart grids. 

Efficient Hash-Based Redactable Signature for Smart Grid Applications

Abstract Recommender systems have been widely used for implementing personalised content on many mobile online services to reduce computational overload and preserve wireless data for users. The underlying mechanisms used for building recommender systems analyse data collected from users to make recommendations. This poses concerns over the privacy of data from users as both service providers and the cloud will have access. Privacy-preserving recommender systems protect user information by incorporating various cryptographic mechanisms to prevent accessing the data. However, existing works are not practical due to the use of heavy cryptography. In this paper, we propose an efficient privacy-preserving recommender system that takes advantage of clustering to improve efficiency. Using a secure clustering mechanism, user data are assigned to multiple clusters before being fed into the recommendation. Our proposed protocols are privacy-preserving and do not leak information that could be used to identify a data subject. The experiments show that our system is efficient and accurate. 

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An efficient privacy-preserving recommender system in wireless networks

Wireless body area networks (WBANs) technology nowadays has become a promising networking paradigm in the Internet of Things (IoT) as it can provide people with high quality of life and high level of medical service. In order to ensure the security and privacy of patients’ sensitive biomedical data and the efficiency of message processing across different devices, it is critical to provide a secure and lightweight authentication scheme for WBANs. In this article, we propose an extra lightweight authentication scheme for mobile-edge computing-enabled WBANs. Two different authentication phases based on the modular square roots technique are designed: one is the intra-BAN authentication between the sensor node and edge node (EN), and the other is the inter-BAN authentication between EN and application provider. The proposed scheme offers robust security by providing comprehensive security analysis. Performance is also evaluated in terms of computation, communication, and storage costs. The evaluation results demonstrate that the proposed scheme achieves a reduction of at least 90% in computation cost and at least 30% in communication cost when compared to four other related schemes.

Junwei Luo

Papers

SGX-based Users Matching with Privacy Protection

A distributed networked system for secure publicly verifiable self-tallying online voting

Efficient Hash-Based Redactable Signature for Smart Grid Applications

An efficient privacy-preserving recommender system in wireless networks

Secure and Lightweight Authentication for Mobile-Edge Computing-Enabled WBANs