Quantum Cryptography and Bell’s Theorem

Abstract

In this article, I would like to show you a glimpse of beauty which one can easily find in the union of cryptography and quantum theory. So this is a story about quanta and ciphers. I will show how quantum mechanics protects the so-called key distribution process in cryptography. The proposed scheme is based on the well-known Bohm’s version of the Einstein-Podolsky-Rosen gedankenexperiment ^1,2; the generalized Bell’s theorem (Clauser - Horne - Shimony - Holt inequalities)^3,4 is used to test for eavesdropping. However, before I proceed any further, let me start with some historical remarks followed by some basic notions of cryptography.