Machine Learning (ML) has become one of the most impactful fields of data
science in recent years. However, a significant concern with ML is its privacy
risks due to rising attacks against ML models. Privacy-Preserving Machine
Learning (PPML) methods have been proposed to mitigate the privacy and security
risks of ML models. A popular approach to achieving PPML uses Homomorphic
Encryption (HE). However, the highly publicized inefficiencies of HE make it
unsuitable for highly scalable scenarios with resource-constrained devices.
Hence, Hybrid Homomorphic Encryption (HHE) -- a modern encryption scheme that
combines symmetric cryptography with HE -- has recently been introduced to
overcome these challenges. HHE potentially provides a foundation to build new
efficient and privacy-preserving services that transfer expensive HE operations
to the cloud. This work introduces HHE to the ML field by proposing
resource-friendly PPML protocols for edge devices. More precisely, we utilize
HHE as the primary building block of our PPML protocols. We assess the
performance of our protocols by first extensively evaluating each party's
communication and computational cost on a dummy dataset and show the efficiency
of our protocols by comparing them with similar protocols implemented using
plain BFV. Subsequently, we demonstrate the real-world applicability of our
construction by building an actual PPML application that uses HHE as its
foundation to classify heart disease based on sensitive ECG data.