With the advancement of Internet of Things (IoT), a large number of electronic devices are connected to the Internet. These connected electronic devices acquire, transmit information and respond to any received actions. In medical ecosystem, hospitals can implement medical diagnosis with medical sensors, especially for remote auxiliary medical diagnosis. But, in this context, patients privacy is paramount importance, and confidentiality of medical data is crucial. Therefore, the main challenge ahead is how to realize remote auxiliary medical diagnosis while protecting confidentiality of the medical data and ensuring patients privacy. In this paper, based on somewhat homomorphic encryption (SHE) scheme addressed by Junfeng Fan and Frederik Vercauteren (FV), we provide the first instance of a new efficient SHE scheme for homomorphic evaluation over Single Instruction Multiple Data (SIMD). We also implement a new set of efficient SIMD homomorphic comparison and division schemes. Based on these findings, we implement efficient privacy-preserving and SIMD homomorphic surf and multi-retina-image matching schemes. Offered functionalities include SIMD homomorphic feature point detection, multi-retina-image matching and lesion detection for the encrypted retinal image of diabetic retinopathy. Finally, we provide a proof-of-concept application implementation towards remote auxiliary diagnosis systems for diabetes in order to showcase the core security and privacy pillars of our solution. In the meantime, our IoT system designed with lattice-based cryptography preserves data confidentiality under quantum computation and quantum computers.

The Internet of Things (IoT) is ubiquitous in our lives. However, the inherent vulnerability of IoT smart devices can lead to the destruction of networks in untrustworthy environments. Therefore, authentication is a necessary tool to ensure the legitimacy of nodes and protect data security. Naturally, the authentication factors always include various sensitive users’ information, such as passwords, ID cards, even biological information, etc. How to prevent privacy leakage has always been a problem faced by the IoT. Zero-knowledge authentication is a crucial cryptographic technology that uses authenticates nodes on the networks without revealing identity or any other data entered by users. However, zero-knowledge proof (ZKP) requires more complex data exchange protocols and more data transmission compared to traditional cryptography technologies. To understand how zero-knowledge authentication works in IoT, we produce a survey on zero-knowledge authentication in privacy-preserving IoT in the paper. First, we overview the IoT architecture and privacy, including security challenges and open question in different IoT layers. Next, we overview zero-knowledge authentication and provide a comprehensive analysis of designing zero-knowledge authentication protocols in various IoT networks. We summarize the advantages of ZKP-based authentication in IoT. Finally, it summarizes the potential problems and future directions of ZKP in IoT.

Users accessing services are often required to provide personal information, for example, age, profession and location, in order to satisfy access polices. We propose a privacy-preserving electronic ticket scheme using attribute-based credentials to protect users' privacy. The benefit of our scheme is that the attributes of a user are certified by a trusted third party so that the scheme can provide assurances to a seller that a user's attributes are valid. The scheme makes the following contributions: (1) users can buy different tickets from ticket sellers without releasing their exact attributes; (2) two tickets of the same user cannot be linked; (3) a ticket cannot be transferred to another user; (4) a ticket cannot be double spent. The novelty of our scheme is to enable users to convince ticket sellers that their attributes satisfy the ticket policies and buy discounted tickets anonymously. This is a step towards identifying an e-ticketing scheme that captures user privacy requirements in transport services. The security of our scheme is proved and reduced to a well-known complexity assumption. The scheme is also implemented and its performance is empirically evaluated.

A Privacy-preserving Verifiable (outsourced) Computation (PVC) protocol enables a resource-constrained client to outsource expensive and sensitive workloads to computationally powerful but possibly untrusted service providers (called workers) and to verify the correctness of the results. In a PVC protocol, the inputs and outputs of the computation are hidden, so that the worker is unable to determine them. This is referred to as the privacy property. A Non-interactive PVC (NPVC) protocol is a PVC protocol without communications between a client and worker, apart from distributing the workloads and results. In the literature, Sparse Matrices (SMs) have been used in NPVC protocols to efficiently hide the inputs and outputs from the worker. However, to the best of our knowledge, how the low density of an SM affects privacy in such NPVC protocols has not been formally analyzed. In this work, we first propose a formal definition of the privacy property of an NPVC protocol with respect to matrix density. We use this definition to demonstrate that all of the SM masking-based NPVC protocols that we know of do not hold this privacy property under the ciphertext-only attack model. We then propose an SM masking construction to modify two of those protocols, chosen because they are state-of-the-art, and prove that the modified protocols hold the privacy property under the chosen-plaintext attack model. Our modifications do not require the client operating matrix inversion, and they are able to keep the same level of high performance and all other properties as the originals.

In cryptography, a ring signature is anonymous as it hides the signer’s identity among other users. When generating the signature, the users are arranged as a ring. Compared with group signatures, a ring signature scheme needs no group manager or special setup and supports flexibility of group choice. However, the anonymity provided by ring signatures can be used to conceal a malicious signer and put other ring members under suspicion. At the other extreme, it does not allow the actual signer to prove their identity and gain recognition for their actions. A deniable ring signature is designed to overcome these disadvantages. It can initially protect the signer, but if necessary, it enables other ring members to deny their involvement, and allows the real signer to prove who made the signed action. Many real-world applications can benefit from such signatures. Inspired by the requirement for them to remain viable in the post-quantum age, this work proposes a new non-interactive deniable ring signature scheme based on lattice assumptions. Our scheme is proved to be anonymous, traceable and non-frameable under quantum attacks.