Division of Modeling in Biology and Medicine Institute of Fundamental Technological Research Polish Academy of Sciences APPLICATION OF DYNAMICAL SYSTEMS IN SECURE COMMUNICATION: CRYPTOGRAPHY, DISCRETE CHAOS, ERGODICITY, MIXING, LYAPUNOV EXPONENTS Chaotic, ergodic and mixing systems share some important features, both from the theoretical and practical point of view. For example chaos-based cryptography has been around for more than decade by now. Most of practical applications need a discretization of continuous dynamical systems. We develop discrete counterparts of the classical concepts like Lyapunov exponents, entropy or chaos. For more details refer to Phys. Lett. A (2008), Phys. Lett. A (2007), IEEE T. Circuits Sys. (2006) and Phys. Rev. Lett. (2004). ANISOTROPIC SUPERFLUID TURBULENCE Superfluid vortex configuration during formation of plane Cuette flow, full story: Eur. J. Mech, B-Fluids 2006. MAIN PAGE