Antonin Voyez

selected publications

1. Nature SREP

   The privacy cost of fine-grained electrical consumption data

   Voyez, Antonin, Allard, Tristan,  Avoine, Gildas and 3 more authors

   May 2025

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   The collection of electrical consumption time series through smart meters grows with ambitious nationwide smart grid programs. This data is both highly sensitive and highly valuable: strong laws about personal data protect it while laws about open data aim at making it public after a privacy-preserving data publishing process. In this work, we study the uniqueness of large scale real-life fine-grained electrical consumption time-series and show its link to privacy threats. Our results show a worryingly high uniqueness rate in such datasets. In particular, we show that knowing 5 consecutive electric measures allows to re-identify on average more than 90% of households in our 2.5M half-hourly electric time series dataset. Moreover, uniqueness remains high even when data is severely degraded. For example, when data is rounded to the nearest 100 watts, knowing 7 consecutive electric measures allows to re-identify on average more than 40% of the households (same dataset). We also study the relationship between uniqueness and entropy, uniqueness and electric consumption, and electric consumption and temperatures, showing their strong correlation.

   @misc{voyez2022unique,
     year = {2025},
     month = may,
     title = {The privacy cost of fine-grained electrical consumption data},
     author = {Voyez, Antonin and Allard, Tristan and Avoine, Gildas and Cauchois, Pierre and Fromont, Elisa and Simonin, Matthieu},
     booktitle = {Nature Scientific Reports},
     doi = {10.1038/s41598-024-78285-7},
     url = {https://www.nature.com/articles/s41598-024-78285-7},
   }

2. SIGKDD

   Analyzing and explaining privacy risks on time series data: ongoing work and challenges

   Allard, Tristan, Asghar, Hira,  Avoine, Gildas and 9 more authors

   Jul 2024

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   Currently, privacy risks assessment is mainly performed as audits conducted by data privacy analysts. In the TAILOR project, we promote a more systematic and automatic approach based on interpretable metrics and formal methods to evaluate privacy risks and to control the tension between data privacy and utility. In this paper, we focus on privacy risks raised by publishing time series datasets, and we survey the methods developed in TAILOR to analyze and quantify privacy risks depending on different publisher and attacker models.

   @misc{sigkdd_analyzing,
     year = {2024},
     month = jul,
     title = {Analyzing and explaining privacy risks on time series data: ongoing work and challenges},
     author = {Allard, Tristan and Asghar, Hira and Avoine, Gildas and Bobineau, Christophe and Cauchois, Pierre and Fromont, Elisa and Monreale, Anna and Naretto, Francesca and Pellungrini, Roberto and Pratesi, Francesca and Rousset, Marie-Christine and Voyez, Antonin},
     booktitle = {Association for Computing Machinery},
     doi = {10.1145/3682112.3682118},
     url = {https://doi.org/10.1145/3682112.3682118},
   }

3. Univ. Rennes

   Privacy Risk Analysis of Large-scale Temporal Data : Application to Electricity Consumption Data

   Voyez, Antonin

   Jul 2023

   Abs Bib PDF

   The leading French electricity distribution manager, Enedis, legally must collect and publish electricity consumption time series. Series from households and companies are highly privacy sensitive. Therefore, the publication is anonymized using threshold aggregates. This work studies the vulnerability of open-sourcing electricity consumption time series. Our first contribution performs a large-scale statistical study of French electricity measurements. In particular, we perform a unique study showing un-anonymized series’ high vulnerability against identification attacks. Our second contribution is a membership inference attack that finds every series forming an aggregate. This attack is based on a variant of the subset-sum problem. Our third contribution is a membership inference attack modelized as a time series classification problem. This attack requires little prior knowledge and can find a specific target in an aggregate. We perform in-depth experiments on the attacks. The results offer insight into the choice of relevant threshold. Finally, we propose a metric estimate the potential vulnerability of individual series.

   @misc{voyez2023phd,
     year = {2023},
     month = jul,
     title = {Privacy Risk Analysis of Large-scale Temporal Data : Application to Electricity Consumption Data},
     author = {Voyez, Antonin},
     booktitle = {Université de Rennes},
     %doi = {},
     %url = {},
   }

4. SECRYPT

   Membership Inference Attacks on Aggregated Time Series with Linear Programming

   Voyez, Antonin, Allard, Tristan,  Avoine, Gildas and 3 more authors

   In 19th International Conference on Security and Cryptography Jul 2022

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   Aggregating data is a widely used technique to protect privacy. Membership inference attacks on aggregated data aim to infer whether a specific target belongs to a given aggregate. We propose to study how aggregated time series data can be susceptible to simple membership inference privacy attacks in the presence of adversarial background knowledge. We design a linear programming attack that strongly benefits from the number of data points published in the series and show on multiple public datasets how vulnerable the published data can be if the size of the aggregated data is not carefully balanced with the published time series length. We perform an extensive experimental evaluation of the attack on multiple publicly available datasets. We show the vulnerability of aggregates made of thousands of time series when the aggregate length is not carefully balanced with the published length of the time series.

   @inproceedings{voyez2022membership,
     year = {2022},
     month = jul,
     title = {Membership Inference Attacks on Aggregated Time Series with Linear Programming},
     author = {Voyez, Antonin and Allard, Tristan and Avoine, Gildas and Cauchois, Pierre and Fromont, Elisa and Simonin, Matthieu},
     booktitle = {19th International Conference on Security and Cryptography},
     organization = {SCITEPRESS-Science and Technology Publications},
     url = {https://hal.archives-ouvertes.fr/hal-03726234/},
   }