Adaptive Threshold Displacement algorithm for removing hidden information from digital images

The growth of the Internet and online social media, especially in recent years, also gave rise to a proliferation of online multimedia content creation and distribution. The use of modern steganography methods - the art of hiding information within multimedia - presents an unprecedented opportunity for malicious uses of these materials. Therefore, developing an effective technique to avoid the distribution of secret data is a significant problem that is addressed in this paper for digital images. We introduce a novel algorithm to remove the steganography information embedded in an image without changing the quality of the image and with no prior knowledge of the utilized steganography technique. Our new algorithm called Adaptive Threshold Displacement (ATD) is applied to images in the spatial domain. ATD divides the whole image into different segments and within a given segment, some pixels are displaced according to their contents as well as their neighboring pixel values. For evaluating the effectiveness of our proposed algorithm, we apply ATD to different images that contain hidden information, embedded using two different widely used steganography techniques. The presented results show that virtually all of the hidden information is destroyed by our proposed ATD algorithm, with a retrieval BER of over 40% in average. However, the quality of the images does not change and the PSNR of the resulting images is above 32 dB.