148,753 research outputs found
Privately Connecting Mobility to Infectious Diseases via Applied Cryptography
Human mobility is undisputedly one of the critical factors in infectious
disease dynamics. Until a few years ago, researchers had to rely on static data
to model human mobility, which was then combined with a transmission model of a
particular disease resulting in an epidemiological model. Recent works have
consistently been showing that substituting the static mobility data with
mobile phone data leads to significantly more accurate models. While prior
studies have exclusively relied on a mobile network operator's subscribers'
aggregated data, it may be preferable to contemplate aggregated mobility data
of infected individuals only. Clearly, naively linking mobile phone data with
infected individuals would massively intrude privacy. This research aims to
develop a solution that reports the aggregated mobile phone location data of
infected individuals while still maintaining compliance with privacy
expectations. To achieve privacy, we use homomorphic encryption, zero-knowledge
proof techniques, and differential privacy. Our protocol's open-source
implementation can process eight million subscribers in one and a half hours.
Additionally, we provide a legal analysis of our solution with regards to the
EU General Data Protection Regulation.Comment: Added differentlial privacy experiments and new benchmark
Rethinking Location Privacy for Unknown Mobility Behaviors
Location Privacy-Preserving Mechanisms (LPPMs) in the literature largely
consider that users' data available for training wholly characterizes their
mobility patterns. Thus, they hardwire this information in their designs and
evaluate their privacy properties with these same data. In this paper, we aim
to understand the impact of this decision on the level of privacy these LPPMs
may offer in real life when the users' mobility data may be different from the
data used in the design phase. Our results show that, in many cases, training
data does not capture users' behavior accurately and, thus, the level of
privacy provided by the LPPM is often overestimated. To address this gap
between theory and practice, we propose to use blank-slate models for LPPM
design. Contrary to the hardwired approach, that assumes known users' behavior,
blank-slate models learn the users' behavior from the queries to the service
provider. We leverage this blank-slate approach to develop a new family of
LPPMs, that we call Profile Estimation-Based LPPMs. Using real data, we
empirically show that our proposal outperforms optimal state-of-the-art
mechanisms designed on sporadic hardwired models. On non-sporadic location
privacy scenarios, our method is only better if the usage of the location
privacy service is not continuous. It is our hope that eliminating the need to
bootstrap the mechanisms with training data and ensuring that the mechanisms
are lightweight and easy to compute help fostering the integration of location
privacy protections in deployed systems
Where have you been? A Study of Privacy Risk for Point-of-Interest Recommendation
As location-based services (LBS) have grown in popularity, the collection of
human mobility data has become increasingly extensive to build machine learning
(ML) models offering enhanced convenience to LBS users. However, the
convenience comes with the risk of privacy leakage since this type of data
might contain sensitive information related to user identities, such as
home/work locations. Prior work focuses on protecting mobility data privacy
during transmission or prior to release, lacking the privacy risk evaluation of
mobility data-based ML models. To better understand and quantify the privacy
leakage in mobility data-based ML models, we design a privacy attack suite
containing data extraction and membership inference attacks tailored for
point-of-interest (POI) recommendation models, one of the most widely used
mobility data-based ML models. These attacks in our attack suite assume
different adversary knowledge and aim to extract different types of sensitive
information from mobility data, providing a holistic privacy risk assessment
for POI recommendation models. Our experimental evaluation using two real-world
mobility datasets demonstrates that current POI recommendation models are
vulnerable to our attacks. We also present unique findings to understand what
types of mobility data are more susceptible to privacy attacks. Finally, we
evaluate defenses against these attacks and highlight future directions and
challenges.Comment: 26 page
Knowing Your Population: Privacy-Sensitive Mining of Massive Data
Location and mobility patterns of individuals are important to environmental
planning, societal resilience, public health, and a host of commercial
applications. Mining telecommunication traffic and transactions data for such
purposes is controversial, in particular raising issues of privacy. However,
our hypothesis is that privacy-sensitive uses are possible and often beneficial
enough to warrant considerable research and development efforts. Our work
contends that peoples behavior can yield patterns of both significant
commercial, and research, value. For such purposes, methods and algorithms for
mining telecommunication data to extract commonly used routes and locations,
articulated through time-geographical constructs, are described in a case study
within the area of transportation planning and analysis. From the outset, these
were designed to balance the privacy of subscribers and the added value of
mobility patterns derived from their mobile communication traffic and
transactions data. Our work directly contrasts the current, commonly held
notion that value can only be added to services by directly monitoring the
behavior of individuals, such as in current attempts at location-based
services. We position our work within relevant legal frameworks for privacy and
data protection, and show that our methods comply with such requirements and
also follow best-practice
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Towards Privacy-Preserving Semantic Mobility Analysis
By analyzing data reflecting human mobility, one can derive patterns and knowledge that are tightly linked to the underlying geography and therefore cannot be applied to another territory or even compared with patterns obtained for another territory. Another problem of mobility analysis is compromising personal privacy, since person identities can be determined based on the regularly visited geographical locations.We here propose an idea for novel approach based on transformation of the spatial component of movement data from the geographic space to an abstract semantic space, inspired by the concept of cartographic chorems. We demonstrate that many visual analytics procedures developed for geographic movement data can be adapted for privacy-preserving mobility analysis based on semantic spaces
A survey on privacy in human mobility
In the last years we have witnessed a pervasive use of location-aware technologies such as vehicular GPS-enabled devices, RFID based tools, mobile phones, etc which generate collection and storing of a large amount of human mobility data. The powerful of this data has been recognized by both the scientific community and the industrial worlds. Human mobility data can be used for different scopes such as urban traffic management, urban planning, urban pollution estimation, etc. Unfortunately, data describing human mobility is sensitive, because people's whereabouts may allow re-identification of individuals in a de-identified database and the access to the places visited by indi-viduals may enable the inference of sensitive information such as religious belief, sexual preferences, health conditions, and so on. The literature reports many approaches aimed at overcoming privacy issues in mobility data, thus in this survey we discuss the advancements on privacy-preserving mo-bility data publishing. We first describe the adversarial attack and privacy models typically taken into consideration for mobility data, then we present frameworks for the privacy risk assessment and finally, we discuss three main categories of privacy-preserving strategies: methods based on anonymization of mobility data, methods based on the differential privacy models and methods which protect privacy by exploiting generative models for synthetic trajectory generation
Privacy-Aware Adversarial Network in Human Mobility Prediction
As mobile devices and location-based services are increasingly developed in different smart city scenarios and applications, many unexpected privacy leakages have arisen due to geolocated data collection and sharing. User re-identification and other sensitive inferences are major privacy threats when geolocated data are shared with cloud-assisted applications. Significantly, four spatio-temporal points are enough to uniquely identify 95\% of the individuals, which exacerbates personal information leakages. To tackle malicious purposes such as user re-identification, we propose an LSTM-based adversarial mechanism with representation learning to attain a privacy-preserving feature representation of the original geolocated data (i.e., mobility data) for a sharing purpose. These representations aim to maximally reduce the chance of user re-identification and full data reconstruction with a minimal utility budget (i.e., loss). We train the mechanism by quantifying privacy-utility trade-off of mobility datasets in terms of trajectory reconstruction risk, user re-identification risk, and mobility predictability. We report an exploratory analysis that enables the user to assess this trade-off with a specific loss function and its weight parameters. The extensive comparison results on four representative mobility datasets demonstrate the superiority of our proposed architecture in mobility privacy protection and the efficiency of the proposed privacy-preserving features extractor. We show that the privacy of mobility traces attains decent protection at the cost of marginal mobility utility. Our results also show that by exploring the Pareto optimal setting, we can simultaneously increase both privacy (45%) and utility (32%)
Predicting and Explaining Privacy Risk Exposure in Mobility Data
Mobility data is a proxy of different social dynamics and its analysis enables a wide range of user services. Unfortunately, mobility data are very sensitive because the sharing of people’s whereabouts may arise serious privacy concerns. Existing frameworks for privacy risk assessment provide tools to identify and measure privacy risks, but they often (i) have high computational complexity; and (ii) are not able to provide users with a justification of the reported risks. In this paper, we propose expert, a new framework for the prediction and explanation of privacy risk on mobility data. We empirically evaluate privacy risk on real data, simulating a privacy attack with a state-of-the-art privacy risk assessment framework. We then extract individual mobility profiles from the data for predicting their risk. We compare the performance of several machine learning algorithms in order to identify the best approach for our task. Finally, we show how it is possible to explain privacy risk prediction on real data, using two algorithms: Shap, a feature importance-based method and Lore, a rule-based method. Overall, expert is able to provide a user with the privacy risk and an explanation of the risk itself. The experiments show excellent performance for the prediction task
Time Distortion Anonymization for the Publication of Mobility Data with High Utility
An increasing amount of mobility data is being collected every day by
different means, such as mobile applications or crowd-sensing campaigns. This
data is sometimes published after the application of simple anonymization
techniques (e.g., putting an identifier instead of the users' names), which
might lead to severe threats to the privacy of the participating users.
Literature contains more sophisticated anonymization techniques, often based on
adding noise to the spatial data. However, these techniques either compromise
the privacy if the added noise is too little or the utility of the data if the
added noise is too strong. We investigate in this paper an alternative
solution, which builds on time distortion instead of spatial distortion.
Specifically, our contribution lies in (1) the introduction of the concept of
time distortion to anonymize mobility datasets (2) Promesse, a protection
mechanism implementing this concept (3) a practical study of Promesse compared
to two representative spatial distortion mechanisms, namely Wait For Me, which
enforces k-anonymity, and Geo-Indistinguishability, which enforces differential
privacy. We evaluate our mechanism practically using three real-life datasets.
Our results show that time distortion reduces the number of points of interest
that can be retrieved by an adversary to under 3 %, while the introduced
spatial error is almost null and the distortion introduced on the results of
range queries is kept under 13 % on average.Comment: in 14th IEEE International Conference on Trust, Security and Privacy
in Computing and Communications, Aug 2015, Helsinki, Finlan
Privacy-Friendly Mobility Analytics using Aggregate Location Data
Location data can be extremely useful to study commuting patterns and
disruptions, as well as to predict real-time traffic volumes. At the same time,
however, the fine-grained collection of user locations raises serious privacy
concerns, as this can reveal sensitive information about the users, such as,
life style, political and religious inclinations, or even identities. In this
paper, we study the feasibility of crowd-sourced mobility analytics over
aggregate location information: users periodically report their location, using
a privacy-preserving aggregation protocol, so that the server can only recover
aggregates -- i.e., how many, but not which, users are in a region at a given
time. We experiment with real-world mobility datasets obtained from the
Transport For London authority and the San Francisco Cabs network, and present
a novel methodology based on time series modeling that is geared to forecast
traffic volumes in regions of interest and to detect mobility anomalies in
them. In the presence of anomalies, we also make enhanced traffic volume
predictions by feeding our model with additional information from correlated
regions. Finally, we present and evaluate a mobile app prototype, called
Mobility Data Donors (MDD), in terms of computation, communication, and energy
overhead, demonstrating the real-world deployability of our techniques.Comment: Published at ACM SIGSPATIAL 201
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