CoPriv: Network/Protocol Co-Optimization for Communication-Efficient Private Inference

TL;DR

CoPriv introduces a joint optimization framework for DNN inference in secure 2-party computation, significantly reducing communication overhead by optimizing both the protocol and network architecture.

Contribution

It proposes a new convolution protocol based on Winograd transformation and a DNN-aware optimization algorithm for communication reduction in secure inference.

Findings

Achieves 2.1x communication reduction over CrypTFlow2 on ResNet models.

Attains nearly 10x online communication savings compared to SNL.

Improves accuracy while reducing communication compared to existing network optimization methods.

Abstract

Deep neural network (DNN) inference based on secure 2-party computation (2PC) can offer cryptographically-secure privacy protection but suffers from orders of magnitude latency overhead due to enormous communication. Previous works heavily rely on a proxy metric of ReLU counts to approximate the communication overhead and focus on reducing the ReLUs to improve the communication efficiency. However, we observe these works achieve limited communication reduction for state-of-the-art (SOTA) 2PC protocols due to the ignorance of other linear and non-linear operations, which now contribute to the majority of communication. In this work, we present CoPriv, a framework that jointly optimizes the 2PC inference protocol and the DNN architecture. CoPriv features a new 2PC protocol for convolution based on Winograd transformation and develops DNN-aware optimization to significantly reduce the inference communication. CoPriv further develops a 2PC-aware network optimization algorithm that is compatible with the proposed protocol and simultaneously reduces the communication for all the linear and non-linear operations. We compare CoPriv with the SOTA 2PC protocol, CrypTFlow2, and demonstrate 2.1x communication reduction for both ResNet-18 and ResNet-32 on CIFAR-100. We also compare CoPriv with SOTA network optimization methods, including SNL, MetaPruning, etc. CoPriv achieves 9.98x and 3.88x online and total communication reduction with a higher accuracy compare to SNL, respectively. CoPriv also achieves 3.87x online communication reduction with more than 3% higher accuracy compared to MetaPruning.