Low-Cost High-Power Membership Inference by Boosting Relativity

Membership inference attacks (MIA) determine whether a specific data point has been used in training of a model [45]. These attacks represent a foundational tool in evaluating the privacy risks of unintentional exposure of information due to training machine learning models on different types of data in a wide range of scenarios. These scenarios encompass diverse settings such as statistical models [19, 2, 44, 36], machine learning as a service [45], federated learning [38, 26, 21], generative models [6], and also privacy-preserving machine-learning [47, 39, 20]. Membership inference attacks originated within the realm of summary statistics on high-dimensional data [19]. In this context, multiple hypothesis testing methods were developed to optimize the trade-off between test power and associated errors for relatively straightforward computations [44, 14, 36].