Biblio

Generalized chaos systems have more complex dynamic behavior than conventional chaos systems. If a generalized response system can be synchronized with a conventional drive system, the flexible control parameters and unpredictable synchronization state will increase significantly. The study first constructs a four-dimensional nonlinear dynamic equation with quadratic variables as a drive system. The numerical simulation and analyses of the Lyapunov exponent show that it is also a chaotic system. Based on the generalized chaos synchronization (GCS) theory, a four-dimensional diffeomorphism function is designed, and the corresponding GCS response system is generated. Simultaneously, the structural and synchronous circuits of information interaction and control are constructed with Multisim™ software, with the circuit simulation resulting in a good agreement with the numerical calculations. In order to verify the practical effect of generalized synchronization, an RGB digital image secure communication scheme is proposed. We confuse a 24-bit true color image with the designed GCS system, extend the original image to 48-bits, analyze the scheme security from keyspace, key sensitivity and non-symmetric identity authentication, classical types of attacks, and statistical average from the histogram, image correlation. The research results show that this GCS system is simple and feasible, and the encryption algorithm is closely related to the confidential information, which can resist the differential attack. The scheme is suitable to be applied in network images or other multimedia safe communications.

Cryptography is a widespread technique that maintains information security over insecure networks. The symmetric encryption scheme provides a good security, but the key exchange is difficult on the other hand, in the asymmetric encryption scheme, key management is easier, but it does not offer the same degree of security compared to symmetric scheme. A hybrid cryptosystem merges the easiness of the asymmetric schemes key distribution and the high security of symmetric schemes. In the proposed hybrid cryptosystem, Serpent algorithm is used as a data encapsulation scheme and Elliptic Curve Cryptography (ECC) is used as a key encapsulation scheme to achieve key generation and distribution within an insecure channel. This modification is done to tackle the issue of key management for Serpent algorithm, so it can be securely used in multimedia protection.