Dana Alsagheer and Hadi Mansourifar, University of Houston, USA

Homomorphic encryption (HE) permits users to perform computations on encrypted data without first decrypting it. HE can be used for privacy-preserving outsourced computation and analysis, allowing data to be encrypted and outsourced to commercial cloud environments for processing while encrypted or sensitive data. HE enables new services by removing privacy barriers inhibiting data sharing or increasing the security of existing services. A convolution neural network (CNN) can be homomorphically evaluated using addition and multiplication by replacing the activation function, such as Rectified Linear Units (ReLU), with a low polynomial degree. To achieve the same performance as the ReLU activation function, we study the impact of applying the ensemble techniques to solve the accuracy problem. Our experimental results empirically show that the ensemble approach can reduce bias, and variance, increasing accuracy to achieve the same ReLU performance with parallel and sequential techniques. We demonstrate the effectiveness and robustness of our method using three datasets: MNIST, FMNIST, and CIFAR-10.

Homomorphic encryption, activation function, ensemble approach.