Grayscale image encryption using a hyperchaotic unstable dissipative system

Here we use a pseudo-random bit generator based on a hyperchaotic unstable dissipative system suitable for encryption. This type of system presents saddle hyperbolic equilibrium points with eigenvalues as follows: two negative real eigenvalue, and one pair of complex conjugated eigenvalues with positive real part. The hyperchaotic system in R⁴ is binarized in order to generate a pseudo-random sequence, that is used to encrypt binary information of a grayscale image via symmetric-key algorithm.