Enhancing Security and Privacy in Modern Text-Based Instant Messaging Communications

Modern society changed the way of communication: instead of communicating face-to-face, people more often communicate using text-based instant messaging (IM) applications. These applications use appropriate protocols to facilitate communication between end users. It is crucial to ensure both the security and an adequate level of privacy for end users. Many existing protocols having the same purpose might be considered potentially suspicious. The reason for this is the usage of encryption - encrypted traffic is often targeted by mass surveillance tools. This paper presents a novel protocol named StegaCloak. By combining cryptography with steganography, this protocol enhances security and privacy in modern text-based IM communication. Furthermore, it addresses one important weakness of other similar protocols - detectability, by hiding real communication within regular chat messages. We described our protocol using two approaches: a simple diagram of messages flow and formal protocol flow notation. The proposed protocol is compared to some of the most well-known IM protocols today, OTR and Signal. Its security is verified using the AVISPA tool, a tool designed for the formal verification of security protocols.