Cryptography between Wonderland and Underland

Abstract

Cryptography is a very broad field, interdisciplinary in nature, and connected to many other areas (in mathematics, computer science, computer systems and engineering). On the one hand, in theoretical cryptography many new notions have been defined, constructed and improved, especially new protocols and cryptosystems that are very powerful and surprising, including solving challenging and even seemingly paradoxical problems. On the other hand, cryptography is often required in actual computing systems, where the computing and communication infrastructure is very dynamic and evolves in a very fast pace. Thus, actual systems may need solutions that are highly constrained, non trivial, and not covered by merely combining existing cryptographic tools and protocols in a black-box fashion. These solutions are the subject of industrial development of specific cryptographic systems that are much less known than their theoretical counterparts. We discuss the interplay between theory of cryptographic protocols and actual industrial cryptographic systems, the differences in specifying, analyzing, modeling, designing and validating in each sub-area, as well as the similarity and the mutual influence between the two sub-areas.