Differentially-Private Data Synthetisation for Efficient Re-Identification Risk Control

Protecting user data privacy can be achieved via many methods, from statistical transformations to generative models. However, all of them have critical drawbacks. For example, creating a transformed data set using traditional techniques is highly time-consuming. Also, recent deep learning-based solutions require significant computational resources in addition to long training phases, and differentially private-based solutions may undermine data utility. In this paper, we propose $\epsilon$-PrivateSMOTE, a technique designed for safeguarding against re-identification and linkage attacks, particularly addressing cases with a high re-identification risk. Our proposal combines synthetic data generation via noise-induced interpolation to obfuscate high-risk cases while maximising the data utility of the original data. Compared to multiple traditional and state-of-the-art privacy-preservation methods on 17 data sets, $\epsilon$-PrivateSMOTE achieves competitive results in privacy risk and better predictive performance than generative adversarial networks, variational autoencoders, and differential privacy baselines. It also improves energy consumption and time requirements by at least a factor of 11 and 15, respectively.