Identification of Steganographic Methods Using a Hierarchical CNN Structure

계층적 CNN 구조를 이용한 스테가노그래피 식별

  • Received : 2019.12.09
  • Accepted : 2019.12.30
  • Published : 2019.12.31

Abstract

Steganalysis is a technique that aims to detect and recover data hidden by steganography. Steganalytic methods detect hidden data by analyzing visual and statistical distortions caused during data embedding. However, for recovering the hidden data, they need to know which steganographic methods the hidden data has been embedded by. Therefore, we propose a hierarchical convolutional neural network (CNN) structure that identifies a steganographic method applied to an input image through multi-level classification. We trained four base CNNs (each is a binary classifier that determines whether or not a steganographic method has been applied to an input image or which of two different steganographic methods has been applied to an input image) and connected them hierarchically. Experimental results demonstrate that the proposed hierarchical CNN structure can identify four different steganographic methods (LSB, PVD, WOW, and UNIWARD) with an accuracy of 79%.

스테그아날리시스(steganalysis)는 스테가노그래피(steganography)에 의해 숨겨진 데이터를 감지하고 복구하기 위한 기법이다. 스테그아날리시스 방법은 데이터 삽입 시 발생하는 시각적, 통계적 변화를 분석하여 숨겨진 데이터를 찾는다. 숨겨진 데이터를 복원하기 위해서는 어떤 스테가노그래피 방법에 의해 데이터가 숨겨졌는지를 알아야 한다. 그러므로 본 논문은 다층 분류를 통해 입력 영상에 적용된 스테가노그래피 방법을 식별하는 계층적 CNN 구조를 제안한다. 이를 위해 4개의 기본 CNN을 각각 입력 영상에 스테가노그래피 방법이 적용되었는지 여부나 서로 다른 두 스테가노그래피 방법 중에 어떤 방법이 적용되었는지를 이진 판별하도록 학습시켰으며, 학습된 CNN을 계층적으로 연결하였다. 실험 결과를 통해 제안된 계층적 CNN 구조는 4개의 서로 다른 스테가노그래피 방법인 LSB(Least Significant Bit Substitution), PVD(Pixel Value Difference), WOW(Wavelet Obtained Weights), UNIWARD(Universal Wavelet Relative Distortion)을 79%의 정확도로 식별할 수 있음을 확인하였다.

Keywords

References

  1. G. Xu and H. Wu, "Structure design of convolution neural networks for steganalysis," IEEE Signal Processing Letters, vol. 23, no. 5, pp. 708-712, 2016. https://doi.org/10.1109/LSP.2016.2548421
  2. J. Fridrich and J. Kodovsky, "Rich models for steganalysis of digital images," IEEE Trans. Inf. Foren. Security, vol. 7, no. 3, pp. 868-882, Jun. 2012. https://doi.org/10.1109/TIFS.2012.2190402
  3. V. Holub and J. Fridrich, "Designing steganographic distortion using directional filters," IEEE Workshop on Information Forensic and Security, 2012.
  4. V. Holub, J. Fridrich, and T. Denemark, "Universal distortion function for steganography in an arbitrary domain," EURASIP J. on Information Security, 2014.
  5. C. Chan and L. Cheng, "Hiding data in images by simple LSB substitution," Pattern Recognition, 37(3), 469-474, 2004. https://doi.org/10.1016/j.patcog.2003.08.007
  6. D. Wu and W. Tsai, "A steganographic method for images by pixel-value differencing," Pattern Recognition, 24, 1613, 2003. https://doi.org/10.1016/S0167-8655(02)00402-6
  7. S. Kang, H. Park, and J.-I. Park, "CNN-based ternary classification for image steganalysis," Electronics, vol. 8, no. 11, 1225, 2019. https://doi.org/10.3390/electronics8111225
  8. P. Bas, T. Filler, and T. Pevny, "Break our steganographic system - the ins and outs of organizing BOSS," International Workshop on Information Hiding, pp. 59-70, 2011.