Discrete-time chaotic encryption systems. III. Cryptographical analysis

For pt. 2 see Proc. Workshop Nonlinear Dynamic Electron. Syst.., Seville, p. 27-32 (1996). This work deals with the cryptographical analysis of a class of discrete-time continuous-value encryption systems. The design of these systems has been treated in Part I. Here, approaches and criteria used in applied cryptography are adopted for continuous-value systems. Two different ciphertext-only attacks on the encryption system are presented in detail. Based on the analysis, improvements of the coder system are suggested.