Kaspersky Blog – 2.23.24
The widespread use of quantum computers in the near future may allow hackers to decrypt messages that were encrypted with classical cryptography methods at astonishing speed. Apple has proposed a solution to this potential problem: after the next update of their OSes, conversations in iMessage will be protected by a new post-quantum cryptographic protocol called PQ3. This technology allows you to change the algorithms of end-to-end encryption with a public key so that they can work on classical non-quantum computers, but will provide protection against potential hacking coming from using future quantum computers.
Source: Apple has released a new way to protect instant messaging in iMessage