Location-based mobile services, while improving user daily life, also raise significant privacy concerns in the sharing of location data. These trajectories indicate users’ traveling behavioural traces with rich semantics derived from open-source information. Behavioral-semantic analysis reveals users’ travelling motivations and underlying behavioral patterns. It contributes to attackers launching inferential attacks for behavior prediction, identity identification, or other privacy invasions, even when the location data is protected. It remains open to the issues of behavioral-semantic privacy-risk quantification and privacy-protection evaluation. This paper aims to reveal such semantic privacy risks of user behaviors arising from the publication of location trajectories in mobile scenarios. We formalize user semantic-mobility process to analyze his underlying behavior patterns. Then, we design semantic inference algorithms conditional on the released trajectory to reason about the observation-based likelihood of the user’s actual staying and transfer behaviours and behavioural-trace tracking. Extensive experiments with real-world data demonstrate their performance on inference accuracy and semantic similarity, offering a quantification criterion for deploying mobile privacy protection.

Crowdsensing-based mobile Internet, while facilitating users’ daily life, also raises privacy concerns because of sharing user location trajectories. Combining with open-source network information, these trajectories reveal the semantics of users’ social behaviors in their travels, thus indicating their behavioral traces. Based on such social mobilities, attackers can explore users’ potential behavioral patterns and launch powerful behavioral-semantic inferential attacks for behavior prediction, identity identification, and threatening users’ location-related mobile privacy. Even through privacy protection, the released similar anonymous semantics may still bring significant privacy gains to such attacks. To the best of our knowledge, there is still no effective technique to counter such attacks and protect user behavioral semantics in mobile Internet services. To this end, this article proposes a posterior behavioral-semantic privacy-preserving solution, BSPri, by simulating the inferential attacks to eliminate the privacy risks associated with released traces. Specifically, we represent the logical association between semantic attributes and propose a similar semantic clustering and ranking method. Then, we formalize the user social-mobility stochastic process to characterize the privacy risks arising from the attacker’s observation of the released trajectory, and define a observation-based posterior privacy authentication criteria to filter anonymous semantics further. Finally, we generate synthetic trajectories with similar anonymity semantics, which bring attackers insignificant privacy gain, for users to participate in applications. Extensive experiments with the real-world data set demonstrate that our BSPri achieves an effective privacy-preserving performance, i.e., rigorous posterior-privacy constraint with limited data-availability loss, such as, distance 752 m$(47$-m closer, compared with our previous work MSP), direction deviation$39.5^{\circ }~(11.5^{\circ }$smaller), and semantic similarity$43.4\%~(8.4\%$closer).

While facilitating user daily lives, the booming development of mobile Internet services raises their privacy concerns because of the need to share travel trajectories. Due to the differences in access patterns and sensitive location attributes, behavioral semantics of user travel suffer from different degrees of leakage risks and have personalized privacy requirements. Semantic mobility-aware personalized privacy protection is still an open research issue in mobile scenarios. To this end, we propose a differentially semantic-generalized behavioral trajectory (DSG-BTra) for achieving privacy-preserving mobile Internet services. Specifically, we first explore the underlying behavioral patterns by formalizing user social mobility. Then, we evaluate the differential privacy sensitivity of user behavior to indicate the risks it faces. Finally, we generalize the behavioral semantics with a sensitivity-quantified strength and generate a DSG-BTra for the user to participate in mobile services. Extensive experiments with real-world data sets demonstrate DSG-BTra achieves flexible balance between privacy protection and application QoS, e.g., reducing the inference probability to 0.18–0.26 with a semantic similarity of 0.3–0.5.

The novel IoT-based data sensing and service mode promotes the booming development of crowdsensing-based mobile communication services (MCSs). MCS facilitates people’s daily lives by providing appropriate services according to the user’s mobile travels. These traveling trajectories, combined with open-source network information, reveal multimodal semantic information implicit in user mobility. Mining these mobile semantics contributes to understanding user mobility more sufficiently. It covers a wide spectrum of applications in mobile scenarios. For service providers, it improves the quality of their services. For mobile users, it helps to design a more rigorous privacy-preserving mechanism. For third-party platforms, such mobility analysis enhances their data management, analysis, and reusage. It has always been an open research issue in mobile computing. We are motivated to conduct a complete and comprehensive survey on semantic mining within the scope of MCS, forming a complete overview of mobile semantic perception. Specifically, we first review existing research works on feature selection. We classify them into five categories, depending on their representation forms. Then, we summarize the research on mobile semantic perception and cluster them to be three groups according to the digging depth of the represented semantics. To complete the overview, we also review the applications of learning algorithms and discuss the open opportunities and challenges for future works.

Synthesizing a fake trajectory with consistent lifestyle and meaningful mobility as the actual one is the most popular way to protect the location privacy in trajectory sharing. Recent location privacy preservation shows a strong personalized requirement from the mobile semantics between users and locations. However, the existing techniques cannot fully satisfy such personalized requirements, resulting in either overprotection or underprotection. It remains open to characterize and quantify the personalized requirement for location privacy preservation. In this article, we propose a mobile semantic-aware privacy model, named MSP. Specifically, we first characterize a new kind of user-related mobile semantic on-location set by constructing a hierarchical semantic tree, according to the user’s roles at locations. Then, a dedicated approach is proposed to evaluate the location’s privacy sensitivity and integrate it into the user-related mobile semantic. Finally, an adaptive privacy-preserving mechanism, MSP, is developed, fully considering the personalized requirement from both the user and the location. With this model in place, mobile semantic-aware synthetic trajectories are constructed adaptively. Extensive experiments with a real-world data set demonstrate that our MSP model can achieve an effective and flexible balance between the personalized privacy preservation and the data availability of synthetic trajectories.