Introduction

Abstract

Cryptography is the science of keeping secrets secret. Assume a sender, referred to here and in what follows as Alice (as is commonly used), wants to send a message m to a receiver, referred to as Bob. She uses an insecure communication channel. For example, the channel could be a computer network or a telephone line. There is a problem if the message contains confidential information. The message could be intercepted and read by an eavesdropper. Or, even worse, the adversary, as usual referred to here as Eve, might be able to modify the message during transmission in such a way that the legitimate recipient Bob does not detect the manipulation.