DNNGuard: An Elastic Heterogeneous DNN Accelerator Architecture against Adversarial Attacks

Recent studies show that Deep Neural Networks (DNN) are vulnerable to adversarial samples that are generated by perturbing correctly classified inputs to cause the misclassification of DNN models. This can potentially lead to disastrous consequences, especially in security-sensitive applications such as unmanned vehicles, finance and healthcare. Existing adversarial defense methods require a variety of computing units to effectively detect the adversarial samples. However, deploying adversary sample defense methods in existing DNN accelerators leads to many key issues in terms of cost, computational efficiency and information security. Moreover, existing DNN accelerators cannot provide effective support for special computation required in the defense methods. To address these new challenges, this paper proposes DNNGuard, an elastic heterogeneous DNN accelerator architecture that can efficiently orchestrate the simultaneous execution of original (target) DNN networks and the detect algorithm or network that detects adversary sample attacks. The architecture tightly couples the DNN accelerator with the CPU core into one chip for efficient data transfer and information protection. An elastic DNN accelerator is designed to run the target network and detection network simultaneously. Besides the capability to execute two networks at the same time, DNNGuard also supports the non-DNN computing and allows the special layer of the neural network to be effectively supported by the CPU core. To reduce off-chip traffic and improve resources utilization, we propose a dynamical resource scheduling mechanism. To build a general implementation framework, we propose an extended AI instruction set for neural networks synchronization, task scheduling and efficient data interaction. We implement DNNGuard based on RISC-V and NVDLA, and evaluate its performance impacts with six target networks and three typical detection networks. Experiment results show that DNNGuard can effectively validate the legitimacy of the input samples in parallel with the target DNN model, achieving an average 1.42x speedup compared with the state-of-the-art accelerators.