Apple's New iMessage, Signal, and Post-Quantum Cryptography

Written by Denis Mandich, Member of the CSA Quantum-Safe Security Working Group and CTO of Qrypt. Apple recently updated their iMessage application with stronger security features, adopting cryptography believed to be secure against attack by quantum computers. They use common end-to-end encryption techniques, but there are aspects unique to their platform. Although they have not explained the justifications for the design decisions, they are cryptographically sound if implemented correctly and there are no bugs in the libraries and software dependencies. Let’s take a look under the hood to understand the new version and what it means for privacy and confidentiality.