Privacy is not just about what an individual user discloses about herself, it also involves what her friends may disclose about her. Multiuser privacy (also called Multiparty Privacy, Interdependent Privacy or Bystander Privacy) is concerned with information pertaining to several individuals and the conflicts that arise when the privacy preferences of these individuals differ. One typical example is a group photo, what one person does with that photo may have privacy implications for the others in the group. This problem happens across many modern technologies, including Social Media, Cloud Computing, Internet of Things / Smart Homes, etc.
We have already made several contributions to multiuser privacy, from generating empirical evidence needed to understand the problem to AI-based methods to resolve multiuser privacy conflicts that we tested with users with successful results.
See below some selected publications we contributed over the years. For recent reviews in specific domains see below (Saqib et al., 2025) (iot/smart devices) and (Such & Criado, 2018) (social media). For multiuser privacy challenges in LLMs and GenAI see (Zhan et al., 2024).
@article{saqib2025bystander,title={Bystander Privacy in Smart Homes: A Systematic Review of Concerns and Solutions},author={Saqib, Eimaan and He, Shijing and Choy, Junghyun and Abu-Salma, Ruba and Such, Jose and Bernd, Julia and Javed, Mobin},journal={ACM Transactions on Computer-Human Interaction (TOCHI)},year={2025},}
@article{such2018multiparty,title={Multiparty Privacy in Social Media},author={Such, Jose and Criado, N},journal={Communications of the ACM (CACM)},volume={61},number={8},pages={74--81},year={2018},}
CUI
Beyond Individual Concerns: Multi-user Privacy in Large Language Models
@inproceedings{zhan2024beyond,author={Zhan, Xiao and Seymour, William and Such, Jose},title={Beyond Individual Concerns: Multi-user Privacy in Large Language Models},booktitle={{ACM} Conversational User Interfaces {(CUI)}},pages={34},year={2024},}
CHI
Multiuser Privacy and Security Conflicts in the Cloud
Eman Alhelali, Kopo Ramokapane, and Jose Such
In Proceedings of the ACM Conference on Human Factors in Computing Systems (CHI), 2023
@inproceedings{alhelali2023multiuser,author={Alhelali, Eman and Ramokapane, Kopo and Such, Jose},title={Multiuser Privacy and Security Conflicts in the Cloud},booktitle={Proceedings of the ACM Conference on Human Factors in Computing Systems ({CHI})},pages={205:1--205:16},year={2023},}
AAMAS
ELVIRA: an Explainable Agent for Value and Utility-driven Multiuser Privacy
Francesca Mosca and Jose Such
In International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS), 2021
@inproceedings{mosca2021elvira,title={ELVIRA: an Explainable Agent for Value and Utility-driven Multiuser Privacy},author={Mosca, Francesca and Such, Jose},booktitle={International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS)},pages={916-924},year={2021},}
TOCHI
Sharing policies in multiuser privacy scenarios: Incorporating Context, Preferences, and Arguments in Decision Making
R Fogues, P Murukannaiah, J Such, and M Singh
ACM Transactions on Computer-Human Interaction (TOCHI), 2017
@article{fogues2017sharing,title={Sharing policies in multiuser privacy scenarios: Incorporating Context, Preferences, and Arguments in Decision Making},author={Fogues, R and Murukannaiah, P and Such, J and Singh, M},journal={ACM Transactions on Computer-Human Interaction (TOCHI)},volume={24},number={1},pages={5},year={2017},}
CHI
Photo Privacy Conflicts in Social Media: A Large-scale Empirical Study
Jose Such, J Porter, S Preibusch, and A Joinson
In Proceedings of the ACM Conference on Human Factors in Computing Systems (CHI), 2017
@inproceedings{such2017photo,title={Photo Privacy Conflicts in Social Media: {A} Large-scale Empirical Study},author={Such, Jose and Porter, J and Preibusch, S and Joinson, A},booktitle={Proceedings of the ACM Conference on Human Factors in Computing Systems (CHI)},pages={3821--3832},year={2017},}
TKDE
Resolving multi-party privacy conflicts in social media
Jose Such and Natalia Criado
IEEE Transactions on Knowledge and Data Engineering (TKDE), 2016
@article{such2016resolving,title={Resolving multi-party privacy conflicts in social media},author={Such, Jose and Criado, Natalia},journal={IEEE Transactions on Knowledge and Data Engineering (TKDE)},volume={28},number={7},pages={1851--1863},year={2016}}
See more related publications in our Publications page.