Multimedia Cryptography based on Liu and Chen Systems

Information security is an important matter in communication systems such as internet communication, multimedia systems, medical imaging, and especially military communication. This paper presents two types of multimedia cryptography; text and image cryptography depending on using Chen and Liu systems. The two systems together are used to generate a secret key to encipher multimedia. First by changing the position of characters in original text and changing position of pixels in original image, then changing the character value itself and pixel value depending on random numbers generated by Liu and Chen systems .The experimental and simulation results show that the proposed system is effective and has a high security level. Due to its key space, high key sensitivity, high entropy , low correlation, strong against differential analysis and finally low time complexity since the same set of numbers must be generated depending in the same key schedule to return original multimedia and this is impossible without knowing exact initial conditions, parameters at the same schedule.