Power Analysis Attack of an AES GPU Implementation

Abstract

In the past, Graphics Processing Unities (GPUs) were mainly used for graphics rendering. In the past 10 years, they have been redesigned and are used to accelerate a wide range of applications, including deep neural networks, image reconstruction and cryptographic algorithms. Despite being the accelerator of choice in a number of important application domains, today’s GPUs receive little attention on their security, especially their vulnerability to realistic and practical threats, such as side-channel attacks. In this work we present our study of side-channel vulnerability targeting a general purpose GPU. We propose and implement a side-channel power analysis methodology to extract all the last round key bytes of an AES (Advanced Encryption Standard) implementation on an NVIDIA TESLA GPU. We first analyze the challenges of capturing GPU power traces due to the degree of concurrency and underlying architectural features of a GPU, and propose techniques to overcome these challenges. We then construct an appropriate power model for the GPU. We describe effective methods to process the GPU power traces and launch a correlation power attack (CPA) on the processed data. We carefully consider the scalability of the attack with increasing degrees of parallelism, a key challenge on the GPU. Both our empirical and theoretical results show that parallel computing hardware systems such as a GPU are vulnerable to power analysis side-channel attacks, and need to be hardened against such threats.