GAP-WF: Graph Attention Pooling Network for Fine-grained SSL/TLS Website Fingerprinting

As an important part of network management, website fingerprinting has become one of the hottest topics in the field of encrypted traffic classification. Website fingerprinting aims to identify the specific webpages in encrypted traffic by observing patterns of traffic traces. Prior studies proposed several machine-learning-based methods using statistical features and deep-learning-based methods using packet length sequences. However, these works mainly focus on the website homepage fingerprinting. In fact, people are usually not limited to visiting the homepage. Compared with the homepage classification of websites, it is more difficult to identify different webpages within the same website due to the traffic traces are very similar. In this paper, we propose the Graph Attention Pooling Network for fine-grained website fingerprinting (GAP-WF). We introduce the trace graph to describe the contextual relationship between flows in webpage loading. Then we utilize the Graph Neural Networks to learn the intra-flow and inter-flow features. Considering different flows may have different importance, we utilize the graph attention mechanism to pay attention to key nodes. We collect four datasets covering three different granularity scenarios to evaluate our proposed method. Experimental results demonstrate that GAP-WF not only achieves the best performance of 99.86% in website homepage fingerprinting, but also outperforms other state-of-art methods in all fine-grained webpage fingerprinting scenarios. Moreover, GAP-WF can achieve better performance with fewer training samples.