Apple SEAR has announced PQ3, a cutting-edge cryptographic protocol for iMessage, providing Level 3 security – the highest protection against quantum attacks. The update includes post-quantum cryptography to safeguard against future quantum computers, making iMessage the only app with this security level. PQ3 introduces a new post-quantum key establishment and rekeying mechanism to protect ongoing messages. A formal verification process by security experts ensures PQ3’s security. The blog post delves into technical details such as hybrid encryption design and post-quantum rekeying to provide users with confidence in the privacy of their communications.
https://security.apple.com/blog/imessage-pq3/