Apple Announces PQ3 Post-Quantum Cryptographic Protocol for iMessage

Apple today announced PQ3, iMessage’s post-quantum cryptographic protocol. The protocol delivers comprehensive protection against sophisticated quantum attacks. This new protocol is considered the biggest advance in iMessage cryptographic security to date.

PQ3 was developed to prevent “Harvest Now, Decrypt Later” attacks, in which malicious actors collect encrypted data with the intention of decrypting it in the future using quantum computers.

Apple states that PQ3 reaches “Level 3” security, ensuring both the initial key establishment and ongoing communication. With iOS 17.4, iPadOS 17.4, macOS 14.4 and watchOS 10.4, this protocol will roll out gradually for supported iMessage conversations starting in March.