|The present disclosure provides a fluid-optical encryption system and a method thereof. The fluid-optical encryption system uses a fluid surface that changes topology over time to modulate the wave front of an electromagnetic signal in an encryption, decryption, authentication or other communication system. The electromagnetic signal can be pulsed or continuous, coherent or non-coherent, and can be optical or in another wavelength range such as micrometer or infrared. The information carrying signal is either transmitted through the fluid system or reflected off the surface of the fluid system. The fluid system time dependent change can be induced by mechanical vibration in the fluid container, distorting the fluid container, acoustic waves through the fluid, or by surface tension changes at the boundary of the fluid cause by electrowetting or electrostatic effects. The fluid surface can exhibit patterns that oscillate or change periodically, or change in a chaotic manner.