Abstract: A new chaos system was established based on the theorem of generalized synchronization and 3D-Lorenz system.The chaos sectuences generated via this system and Arnold' s cat map have better pseudo-random properties. A message encryption and hiding scheme was also established on the system and Arnold's cat map. The scheme is successful to encrypt and decrypt message. Ciphertexts are sensitive to the parameters and initial conditions of the chaos system. Numerical simulations show that our scheme is effective to be used in network communication. It shows that this scheme has good security.

Key words: Generalized synchronization theorem, Encryption and hiding scheme, Pseudo-random properties of chaos sequence