Apple has announced an upgrade to the cryptographic security of its iMessage platform, introducing PQ3, a post-quantum cryptographic protocol which provides extensive defences against highly sophisticated attacks.
In a blog post Apple described PQ3 as the most significant cryptographic security upgrade in iMessage history. The protocol offers compromise-resilient encryption and is designed to protect against potential future threats posed by quantum computers. PQ3 achieves what Apple refers to as “Level 3 security,” providing robust protection for both initial key establishment and ongoing message exchange.
PQ3 will gradually roll out for supported iMessage conversations starting with iOS 17.4, iPadOS 17.4, macOS 14.4, and watchOS 10.4 in March. The protocol is already available in the latest beta versions of these updates. However, visionOS, which runs on Apple’s Vision Pro mixed reality headset, will not support PQ3 during the initial rollout.
PQ3’s introduction marks a significant step in enhancing the security of iMessage conversations. While iMessage already supports end-to-end encryption, existing cryptographic protocols could potentially be vulnerable to future quantum computing advances. PQ3 is specifically designed to defend against “Harvest Now, Decrypt Later” attacks, where attackers collect encrypted data in anticipation of decrypting it with future quantum computers.
Apple stressed the importance of ensuring all devices in an iMessage conversation are updated to the latest software versions to benefit from PQ3’s enhanced security features. The company plans for PQ3 to fully replace iMessage’s existing cryptography protocol in all supported conversations later this year.
