Abstract
A new cryptosystem approach based on two non-linear systems combined to satisfy a high degree of signal transmission security. These systems are Lorenz system and Rossler system. Each chaotic system has a completely different output bit stream. The system uses a stream cipher, in which the encryption key varies continuously. Therefore, a design of a secure communication system that is robust to different types of attacks such brute force attack is very important. One of the main properties of this system is the ability to retrieve the data transmitted through a noisy environment. The proposed system is a novel stream cipher which is based on combining two non-linear systems that are used in digital communication system. The key size of the system will exceed 576, which provide 2576 key space. Hence, this huge key space will provide a high security for plaintext against a brute force attack.