A High-Rate Hidden Communications Channel

Hidden communications creates a capability to transfer data between entities secretly. Steganography techniques can be used to hide the existence of a communication channel within a multimedia carrier (may be image, video, or audio). Quantization Index Modulation (QIM) is a technique of steganography based on quantizing the carrier coefficients. In single embedding in QIM, each sample is quantized once to carry a single bit of the secret message data. Double embedding in QIM developed by Sarkar and Manjunath in 2009, to increase the transferred data rate where a single sample is quantized twice to carry two bits in time. In this paper, multiple embedding in a QIM framework with multi quantization vectors is developed to have more increasing in data transmission rate. A structured scheme of Multiple Trellis-Coded Quantization jointed with Multiple Trellis-Coded Modulation (MTCQ/MTCM) is proposed as the heart of our approach to be used to generate the stego-cover space. Simulation results in case of using images as cover-works indicate that the Peak Signal-to-Noise Ratio (PSNR) between the host and the altered images is greater than 40 dB. More over, increasing the coding states and/or the coding multiplicity results an altered space with low correlated coefficients, thus improving the transferred data detection error rate performance.