We will present our recent theoretical results on characterizing the achievable secrecy rates in cognitive and two way channels. In particular, we will unveil the critical role of randomized scheduling and power allocation in enhancing the achievable secrecy rate region for the two way channel. In the cognitive scenario, we use a game theoretic formulation to demonstrate the ability of the secondary users to trade noise for bits resulting in a unique Nash Equilibrium point which is mutually beneficial for the two users. Finally, we will overview our recent efforts in designing practical security overlays for Wi-Fi networks inspired by information theoretic principles.