CRYPTOGRAPHY - Entropy and randomness

Contents

Introduction

In information theory, the entropy of a random variable is the average level of "information", "surprise", or "uncertainty" inherent to the variable's possible outcomes.

Concepts

Pseudorandomness

Pseudorandomness

Oblivious pseudorandomness

Cloudflare (Privacy Pass context): an oblivious PRF (OPRF) is a protocol between a server S and a client C. In the protocol, S holds a key K for some PRF F and C holds an input x. The security goal is that C receives the output y = F(K,x) without learning the key K and S does not learn the value x.