-In the well-known "prisoners' problem", a representative example of steganography, two persons attempt to communicate covertly without alerting the warden. One approach to achieve this task is to embed the message in an innocent-looking cover-media. In our model, the message contents are scattered in the cover in a certain way that is based on a secret key known only to the sender and receiver. Therefore, even if the warden discovers the existence of the message, he will not be able to recover it. In other words a covert or subliminal communication channel is opened between two persons who possess a secret key to reassemble its contents. In this article, we propose a video or audio steganographic model in which the hidden message can be composed and inserted in the cover in real-time. This is realized by designing and implementing a secret key steganographic micro-architecture employing Field Programmable Gate Arrays FPGA.