With increased global interconnectivity, reliance on network services and Internet communication, real-time transport system security has become an issue, which cannot be ignored. Encryption is viewed as a salvation to protect the real-time transport system from intrusion and computer-virus attacks. A plenty of applications like real-time communications for the web, Voice over IP (VOIP) etc. These are all depending on real-time secure transport system. This paper gives an overview of recent developments in encryption techniques. And it also describes the ongoing researches and applications on encryption techniques used in Human-Computer Interaction (HCI), such as using encryption techniques as VOIP and emergency Mobile Ad-hoc Network, etc.