Processing sensitive information like biometric or biomedical signals in a non-trusted scenario, while ensuring that the privacy of the involved parties is preserved, requires that new tools and solutions are developed. In this project we investigate the possibility of processing signals in the encrypted domain for privacy-aware treatment of sensitive information. By relying on advanced cryptographic primitives like homomorphic encryption, multiparty computation and zero knowledge protocols, we will analyse the possibility of developing secure signal processing primitives like linear transforms, scalar products or FIR filters capable of operating on encrypted data. The developed signal processing primitives will be assembled into a set of basic pattern recognition tools (e.g. neural networks or classifiers) forming the basis for the analysis and interpretation of encrypted signals. At an even higher level, the pattern recognition primitives will be applied to practical scenarios involving the treatment of biometric signals, like face or iris images, or other kinds of sensitive data, like biomedical signals. The requirements stemming from the application level, including those raised by the current privacy regulation, will be considered, so to cast the activity into a practical set up. The architectural and data flow constraints will be considered as well, so to encompass all the levels of the addressed scenario.
The overall goal of the current project is to foster the advancement of signal processing tools (and the underlying cryptographic primitives and protocols) that work directly on encrypted signals, with a particular focus on those tools that allow the privacy-preserving treatment of sensitive information. The project will include both a theoretical and a practical part. The former will be devoted to the development of a general theory of signal processing operations in the encrypted domain, and to the identification of the security vs efficiency trade-offs that characterise the theoretical framework. The latter, will focus on the application of the theoretical concepts to the protection of sensitive information, with the development of suitable protocols wherein the cryptographic and signal processing tools cooperate together.