Crypto Reading Group on quantum computing | Huanhuan Chen & Bruce Xu, Classical Security Proofs, Game Hopping and the Random Oracle Model

Abstract: This talk introduces fundamental techniques for proving security in classical cryptography, with an emphasis on game hopping and the random oracle model. We will discuss how security arguments are structured as sequences of games and how the random oracle model simplifies the analysis of cryptographic constructions. As a first example, we will examine how a random oracle can be used to construct a secure pseudorandom function (PRF) and subsequently a message authentication code (MAC). As a second example, we will explore the role of the random oracle in the Fujisaki–Okamoto transformation and its security proof.