A novel blind detector for additive noise steganography in JPEG decompressed images

This paper proposes a novel universal steganalyzer for additive noise steganography in JPEG decompressed images. On the basis of the influence of the message embedding on the statistical distributions of alternating current (ac) discrete cosine transform (DCT) coefficients, we first develop a new steganalytic feature which is defined as the ratio between different ranges of the normalized ac coefficients histogram. Then a powerful blind detector is constructed with the proposed one-dimensional (1-D) feature. Extensive experimental results demonstrate that the proposed steganalyzer outperforms the existing state-of-the-art schemes significantly and even can detect the additive noise steganography effectively at a very low embedding rate. In addition, our method using a 1-D feature is not only practical and real-time, but also can provide a better control of the false positive rate and the false negative rate by adjusting the detection threshold. Moreover, the proposed feature can also be used to identify JPEG compression besides steganalysis, which indicates that our method has a great promise in practical applications.