US Patent 11949770 Method and system for confidential classification of data

A computer platform includes an artificial neural network (ANN) as well as a classifier. The ANN is configured, after a learning phase, to transform an input data vector into a discriminating feature vector having a smaller dimension. A user then generates, from a plurality of reference data vectors, the same plurality of reference feature vectors, which are encrypted in an encryption module using the public key of a homomorphic cryptosystem and stored in a reference database of the platform. When the user requests the classification of an input data vector, the ANN, or a copy thereof, provides the classifier with a corresponding discriminating feature vector (y). Distances from the vector to the different reference feature vectors are calculated in the homomorphic domain and the index of the reference feature vector closest to y, i.e. the identifier i