With iOS 17.4, set to arrive in March 2024, Apple is bringing a new cryptographic security feature to iMessage called PQ3. This "groundbreaking" and "state-of-the-art" protocol provides "extensive defenses against even highly sophisticated quantum attacks," according to Apple. Let's break down what that means.
Apple's iMessage service already supports end-to-end encryption, but security researchers recognize that existing cryptographic protocols used by messaging apps rely on mathematical problems that could potentially be solved by future quantum computers.
To stay ahead of the cryptographic curve and mitigate risks from future quantum computers, the PQ3 messaging protocol reaches what Apple calls Level 3 security — providing protocol protections that surpass those in all other widely deployed messaging apps. According to Apple, PQ3 achieves this in the following ways:
- Dual Approach: PQ3 combines current Elliptic Curve algorithms with new post-quantum algorithms, ensuring defense against both classical and quantum decryption methods.
- Future-Proof Privacy: PQ3 is specifically designed to safeguard against "Harvest Now, Decrypt Later" attacks, where encrypted data is stored for future decryption with quantum computers.
- End-to-End Encryption: Like its predecessors, PQ3 maintains Apple's commitment to end-to-end encryption, ensuring that only the sender and receiver can read the messages.
- Forward Secrecy: This feature means that even if a key is compromised in the future, past communications remain secure.
- Backward Compatibility: PQ3 is designed to be compatible with existing cryptographic protocols, ensuring a smooth transition and interoperability.
- User Transparency: The complexity of PQ3 operates seamlessly in the background, providing users with a familiar, user-friendly experience without compromising on security.
- Regular Key Refreshing: PQ3 includes mechanisms for regularly updating cryptographic keys, further enhancing security against potential long-term attacks.
Apple says its implementation of PQ3 sets a new standard in messaging app security, and reflects the company's deep commitment to privacy and security in the quantum computing era. The protocol will be rolled out across Apple devices in March, starting with iOS 17.4, iPadOS 17.4, macOS 14.4, and watchOS 10.4. Apple says PQ3 is already in the latest beta versions of these updates, which are available now to registered developers and public beta testers.
