Privacy preserving distributed beamforming based on homomorphic encryption

The last few years have shown a growing interest in distributed noise reduction for speech enhancement in wireless acoustic sensor networks. With this new generation of speech processing algorithms, part of the processing is done at processors not necessarily owned by the user. As a consequence, privacy of the users might be at risk. One risk that underlies such distributed speech enhancement systems is the risk of eavesdropping by untrusted parties. To address these privacy issues, we present how a distributed beamformer can be turned into a privacy preserving distributed beamformer using so-called homomorphic encryption techniques and semi-trusted third parties.