"Selective Hybrid Chaotic-Based Cipher for Real-Time Image Application

Abstract

Confusion and diffusion are the two main principles in encryption. Confusion is a process that drastically changes data from the input to the output. In order to make it right, we have to make the relation between the key and cipher-text as complex as possible. On the other hand, diffusion means that changing a single character of the input will change many characters of the output. In other words, we can say that the output bits should depend on the input bits in a very complex way, so if we change one bit in the plain-text, the cipher-text will change completely. Many chaos-based algorithms were implemented with a chaotic map called the Skew Tent Map (STM), which we address and evaluate in this paper. Our proposed hybrid encryption scheme combines both stream and block ciphering algorithms to achieve the required level of security with the minimum encryption time. The proposed chaos-based cryptosystem uses the STM as a substitution based on a lookup table and STM as a generator to change the byte position to achieve the required confusion and diffusion effects. There is no need to have the inverse or the reverse of the generator in our proposed cryptosystem. The robustness of the proposed cryptosystem was proven by the performance and security analysis, as well as the high encryption speed (throughput).