With the ever-increasing growth of data communication, the need for security and privacy has become a strong necessity. In these conditions, the necessity of new powerful encryption techniques becomes a crucial issue. In this paper Cellular Automata (CA) are applied to construct cryptography algorithms. We present an encryption system implemented on a structure of Hybrid Additive Cellular Automata (HACA) used for securing the medical data sent over the internet. The experimental results prove the power of cellular automata encryption systems. The method supports both software and hardware implementation. In this paper we present a fully functional software application for the data encryption of multimedia medical content.