Apple Beefs Up iMessage With Quantum-Resistant Encryption

Apple is rolling out the post-quantum PQ3 protocol to iMessage starting in March across iOS/iPadOS 17.4, macOS 14.4, and watchOS 10.4, rebuilding its messaging cryptography into a hybrid PQC/ECC design that uses NIST’s Kyber (ML-KEM) and aims to secure both key establishment and ongoing messages (its so-called Level 3). Formal analyses from ETH Zürich (Tamarin) and the University of Waterloo support PQ3, while Signal disputes Apple’s comparisons and highlights its own machine-verified proofs for PQXDH; experts like Bruce Schneier endorse crypto agility but caution on PQC maturity. Apple plans full PQ3 adoption across supported conversations in 2024 to mitigate long-term risks such as “harvest now, decrypt later.”