Apple Announces 'Groundbreaking' New Security Protocol for iMessage

Apple today announced a new post-quantum cryptographic protocol for iMessage called PQ3. Apple says this "groundbreaking" and "state-of-the-art" protocol provides "extensive defenses against even highly sophisticated quantum attacks."

General Apps Messages
Apple believes the PQ3 protocol's protections "surpass those in all other widely deployed messaging apps," according to its blog post:

Today we are announcing the most significant cryptographic security upgrade in iMessage history with the introduction of PQ3, a groundbreaking post-quantum cryptographic protocol that advances the state of the art of end-to-end secure messaging. With compromise-resilient encryption and extensive defenses against even highly sophisticated quantum attacks, PQ3 is the first messaging protocol to reach what we call Level 3 security — providing protocol protections that surpass those in all other widely deployed messaging apps. To our knowledge, PQ3 has the strongest security properties of any at-scale messaging protocol in the world.

PQ3 will be gradually rolling out for supported iMessage conversations starting with iOS 17.4, iPadOS 17.4, macOS 14.4, and watchOS 10.4 in March, and it is already in the latest beta versions of these updates, according to Apple. visionOS will not support the PQ3 protocol during the initial rollout, the company confirmed.

Apple says PQ3 will fully replace iMessage's existing cryptography protocol within all supported conversations later this year. All devices in an iMessage conversation must be updated to the above software versions or later to be eligible.

Post-Quantum Cryptography

iMessage already supports end-to-end encryption, but existing cryptographic protocols that are commonly used by messaging apps rely on mathematical problems that could potentially be solved by future quantum computers.

PQ3 is designed to protect users against "Harvest Now, Decrypt Later" attacks, in which malicious actors collect large amounts of encrypted data now and store it in hopes they will be able to decrypt it with a quantum computer in the future:

Although such quantum computers don't yet exist, extremely well-resourced attackers can already prepare for their possible arrival by taking advantage of the steep decrease in modern data storage costs. The premise is simple: such attackers can collect large amounts of today's encrypted data and file it all away for future reference. Even though they can't decrypt any of this data today, they can retain it until they acquire a quantum computer that can decrypt it in the future, an attack scenario known as Harvest Now, Decrypt Later.

Apple says PQ3 achieves what it calls "Level 3" security, meaning it secures "both the initial key establishment and the ongoing message exchange."

iMessage PQ3
For deeply technical details about the protocol, read the Apple Security Research blog post.

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Top Rated Comments

TechnoMonk Avatar
21 weeks ago

I hope they will also update iMessage with ui features. Whatsapp is just so much easier and intuitive to use, that‘s why nobody is using iMessage in Europe.
I tried WhatsApp, it’s pretty much spam magnet. Luckily for me , almost every one I know uses iMessage. For those who don’t, I just text.
Score: 47 Votes (Like | Disagree)
Pezimak Avatar
21 weeks ago
Everyone will still use bloody WhatsApp ?
Score: 39 Votes (Like | Disagree)
Squozen Avatar
21 weeks ago

I hope they will also update iMessage with ui features. Whatsapp is just so much easier and intuitive to use, that‘s why nobody is using iMessage in Europe.
No, people use WhatsApp in Europe because it’s cross-platform and a lot of people use Android. Adding features to iMessage won’t increase EU usage in the slightest.
Score: 36 Votes (Like | Disagree)
toobravetosave Avatar
21 weeks ago
ok cool now release a cross platform client so your users can be secure no matter who they talk to :)
Score: 36 Votes (Like | Disagree)
spazzcat Avatar
21 weeks ago

I hope they will also update iMessage with ui features. Whatsapp is just so much easier and intuitive to use, that‘s why nobody is using iMessage in Europe.
You are used to it; the UI isn't better than messages or more intuitive.
Score: 33 Votes (Like | Disagree)
0339327 Avatar
21 weeks ago
Governments around the world already rely on iPhones and iMessage for security. This will only enhance the adoption.

I think this is also a large push towards giving customers a reason to stick with iPhone after RCS introduction.

Of course, WhatsApp is far more popular and is controlled by the untrusted Meta.
Score: 21 Votes (Like | Disagree)