We study the problem of privacy-preserving $k$-means clustering in the horizontally federated setting.
Existing federated approaches using secure computation suffer from substantial overheads and do not offer output privacy.
The work provides enhancements to both differentially private (DP) and secure computation components to achieve better speed, privacy, and accuracy.
By utilizing the computational DP model, a lightweight, secure aggregation-based approach is designed, achieving significant speed improvement and improved utility.