#AppleCryptoUpdate Apple has announced a significant cryptographic security upgrade for iMessage with the introduction of PQ3, a post-quantum cryptographic protocol designed to protect against potential threats from future quantum computers. Here's what's new:

*Key Features:*

- *Post-Quantum Cryptography*: PQ3 uses new public key algorithms to ensure secure communication, even against powerful quantum computers.

- *Level 3 Security*: PQ3 reaches the highest level of security for messaging apps, surpassing existing systems with its advanced protections.

- *Hybrid Design*: Combines new post-quantum algorithms with current Elliptic Curve algorithms for added security.

- *Rekeying Mechanism*: PQ3 introduces a periodic post-quantum rekeying mechanism to limit the impact of key compromises and provide self-healing properties.

*How PQ3 Works:*

- *Initial Key Establishment*: PQ3 generates a post-quantum encryption key during the initial conversation setup, protecting all communication from potential quantum threats.

- *Ongoing Rekeying*: The protocol updates encryption keys regularly, ensuring that even if a key is compromised, the conversation remains secure.

*Security Benefits:*

- *Protection Against Quantum Attacks*: PQ3 safeguards user conversations from potential quantum computer threats.

- *Enhanced Security Properties*: Formal verification methods provide strong assurances of the protocol's security.

*Availability:*

PQ3 will roll out with the public releases of iOS 17.4, iPadOS 17.4, macOS 14.4, and watchOS 10.4. iMessage conversations between devices supporting PQ3 will automatically upgrade to the post-quantum encryption protocol.¹