Flow-based Attribute-driven Privacy
A bridge between features and evidence for binary attribute-driven perfect privacy
Perfect privacy requires the log-likelihood-ratio to be zero resulting in no strength-of-evidence.This work presents an approach based on normalizing flow that maps a feature vector into a latent space where the strength-of-evidence, related to the binary attribute, and an independent residual are disentangled.It can be seen as a non-linear discriminant analysis where the mapping is invertible allowing generation by mapping the latent variable back to the original space.This framework allows to manipulate the log-likelihood-ratio of the data and thus to set it to zero for privacy.We show the applicability of the approach on an attribute-driven privacy task where the sex information is removed from speaker embeddings.Results on voxceleb2 dataset show the efficiency of the method that outperforms in terms of privacy and utility our previous experiments based on adversarial disentanglement.
