Privacy-Preserving Indoor Trajectory Matching with IoT Devices.

With the rapid development of the Internet of Things (IoT) technology, Wi-Fi signals have been widely used for trajectory signal acquisition. Indoor trajectory matching aims to achieve the monitoring of the encounters between people and trajectory analysis in indoor environments. Due to constraints ofn the computation abilities IoT devices, the computation of indoor trajectory matching requires the assistance of a cloud platform, which brings up privacy concerns. Therefore, this paper proposes a trajectory-matching calculation method that supports ciphertext operations. Hash algorithms and homomorphic encryption are selected to ensure the security of different private data, and the actual trajectory similarity is determined based on correlation coefficients. However, due to obstacles and other interferences in indoor environments, the original data collected may be missing in certain stages. Therefore, this paper also complements the missing values on ciphertexts through mean, linear regression, and KNN algorithms. These algorithms can predict the missing parts of the ciphertext dataset, and the accuracy of the complemented dataset can reach over 97%. This paper provides original and complemented datasets for matching calculations, and demonstrates their high feasibility and effectiveness in practical applications from the perspective of calculation time and accuracy loss.