Methods and systems for secure electronic data communication over public communication networks. In a Feistel type common key block encrypting process in which an SPN type F function having a nonlinear conversion section and a linear conversion section is repeatedly executed a plurality of rounds. Disclosed methods and systems consider a gestural vocabulary of a predefined number of user specified static andor dynamic hand gestures that are mapped with a database to convey messages. Such ligands are preferably bound to primary moieties through polyfunctional manifold compounds.