AMR Steganalysis based on Adversarial Bi-GRU and Data Distillation

Abstract

Existing AMR (Adaptive Multi-Rate) steganalysis algorithms based on pitch delay have low detection accuracy on samples with short time or low embedding rate, and the model shows fragility under the attack of adversarial samples. To solve this problem, we design an advanced AMR steganalysis method based on adversarial Bi-GRU (Bi-directional Gated Recurrent Unit) and data distillation. First, Gaussian white noise is randomly added to part of the original speech to form adversarial data set, then artificially annotate a small amount of voice to train the model. Second, perform three transformations of 1.5 times speed, 0.5 times speed, and mirror flip on the remaining original voice data, then put them into Bi-GRU for classification, and the final predicted label obtained by the decision fusion corresponds to the original data. All data with the label is put back into the Bi-GRU model for final training at last. What needs to be pointed out is that each batch of final training data includes normal and adversarial samples. This method adopts a semi-supervised learning method, which greatly saves the resources consumed by manual labeling, and introduces adversarial Bi-GRU, which can realize the two-direction analysis of samples for a long time. Based on improving the detection accuracy, the safety and robustness of the model are greatly improved. The experimental results show that for normal and adversarial samples, the algorithm can achieve accuracy of 96.73% and 95.6% respectively.