Auditing Key Transparency

Mari Galicer, Kevin Lewi, Thibault Meunier

Real World Crypto Symposium 2025. Sofia, Bulgaria. March 2025.

Abstract

In 2023, WhatsApp announced its deployment of key transparency, a feature which aims to decrease the trust placed on a centralized server when distributing public keys used for end-to-end encrypted messaging. Similar deployments have been announced for Apple iMessage and ProtonMail. This talk discusses the integration between WhatsApp and Cloudflare to audit the key transparency data structure within a live environment.