Co-designing for Compliance: Multi-party Computation Protocols for Post-Market Fairness Monitoring in Algorithmic Hiring

ACM Conference on Fairness, Accountability, and Transparency (FAccT), pp. 7498–7521

Abstract

Post-market fairness monitoring is now mandated to ensure fairness and accountability for high-risk employment AI systems under emerging regulations such as the EU AI Act. However, effective fairness monitoring often requires access to sensitive personal data, which is subject to strict legal protections under data protection law. Multi-party computation (MPC) offers a promising technical foundation for compliant post-market fairness monitoring, enabling the secure computation of fairness metrics without revealing sensitive attributes. Despite growing technical interest, the operationalization of MPC-based fairness monitoring in real-world hiring contexts under concrete legal, industrial, and usability constraints remains unknown. This work addresses this gap through a co-design approach integrating technical, legal, and industrial expertise. We identify practical design requirements for MPC-based fairness monitoring, develop an end-to-end, legally compliant protocol spanning the full data lifecycle, and empirically validate it in a large-scale industrial setting. Our findings provide actionable design insights as well as legal and industrial implications for deploying MPC-based post-market fairness monitoring in algorithmic hiring systems.

Authors 8

1. Changyang He

   Harbin Institute of Technology · Max Planck Institute for Security and Privacy

   Affiliation as printed

   Max Planck Institute for Security and Privacy, Bochum, Germany, and Harbin Institute of Technology, Shenzhen, Shenzhen, China

2. Nina Baranowska Aachen

   Leiden University

   Affiliation as printed

   Leiden University, Leiden, Netherlands

3. Josu Andoni Eguíluz Castañeira

   Universitat Pompeu Fabra

   Affiliation as printed

   Universitat Pompeu Fabra, Barcelona, Spain, and InfoJobs, Barcelona, Spain

4. Guillem Escriba
   Affiliation as printed

   InfoJobs, Barcelona, Spain

5. Matthias Immanuel Jüntgen

   Max Planck Institute for Security and Privacy · Ruhr University Bochum

   Affiliation as printed

   Max Planck Institute for Security and Privacy, Bochum, Germany, and Ruhr University Bochum, Bochum, Germany

6. Anna Via
   Affiliation as printed

   InfoJobs, Barcelona, Spain

7. Frederik Zuiderveen Borgesius

   Radboud University Nijmegen

   Affiliation as printed

   Radboud University, Nijmegen, Netherlands

8. Asia J. Biega

   Max Planck Institute for Security and Privacy

   Affiliation as printed

   Max Planck Institute for Security and Privacy, Bochum, Germany