Explaining cryptographic systems

Abstract

Modern cryptography can achieve levels of security and authentication that non-specialists find literally incredible. Techniques including information-hiding protocols, zero-knowledge proofs and public key cryptosystems can be used to support applications like digital signatures, digital cash, on-line poker and secure voting in ways that are provably secure—far more secure than the traditional systems they replace. This paper describes simple versions of such applications that have been used to give school-children and the general public a broad understanding of what can be achieved, and how. The material has been extensively and successfully used by the authors in schools, science festivals and with undergraduates, and even postgraduate specialists.