iMessage, it comes with every iDevice!
Regardless of if you own an iPhone, iPad, iWatch or a Mac, iMessage, as well as FaceTime, is preinstalled. Usually, it will use your SIM number for outgoing messages, however, you can choose to add one or more email addresses and add one of them as your outgoing messenger address.
iMessage also has a block feature, so you do not need to worry about spammers. Apps and emojis/Memojies make iMessage a fun way to communicate and, additionally, you can attach any file to send to any other iMessage users.
Of course, within the Apple Garden, you can share to iMessage from any given app. For example, a link that would show the headline and headline picture of an article to other users, or the music you're just listening to on Apple Music…
Plus you can share locations in Apple Maps. iMessage even has apps to play games between two iMessage users. Group chats etc.
When you share photos, you can share them as a single picture or as a collection.
Overall, that all sounds great, and combine it with "what happen on your iPhone, stays on your iPhone" and it should be every Apple fanboy's wet dream.
The big question is, should you use it?
Well, first things first, iMessage was introduced in 2011 by Apple. It is one of the oldest still operating E2EE (end-to-end encryption) messengers. The standard message app in Apple's iPhone sends normal SMS in green, and if the other end has an iDevice, they will receive the messages, encrypted, and showing in blue.
Apple claims that because your messages are end-to-end encrypted, no one, not even Apple, can read them. They also cannot see your attachments, pictures, files etc.
However, this is not entirely true! Apple's iCloud backups are the loophole where Apple can get hold of your messages…
Apple does a backup of all your messages in the iCloud. This is so you can receive all messages on all your iDevices, and to restore iMessage once you get a new device.
Keep in mind that while E2EE is not fundamentally broken, the encryption key, however, might have a backup in the iCloud.
This is only the case if you enable iCloud backup. The messages would still be encrypted, but your actual encryption key would be in an iCloud backup!
iMessage can be disabled from saving a backup to the iCloud within the iCloud settings. However, bear in mind, you might have that key already in the cloud! So, before setting up iMessage, disable iMessage to iCloud in settings or, as I would recommend, do not use iCloud at all. You can sign out of iCloud entirely and still use the Apple Store and iMessage.
In 2020, Apple actually planned to encrypt the entire iCloud, the plan did not go through though as the FBI complained (allegedly) that it would make it impossible for them to procure evidence against iPhone users.
More recently, and in a blaze of unwanted publicity, Apple revealed it can also scan photos stored on iPhones and the iCloud for images showing child abuse. (see CSAM).
Apple also scans iMessages then warns children about sexually explicit photos. This, of course, introduces a serious moral dilemma, and we need to acknowledge that what happens on your iPhone might stay on your iPhone but that Apple still polices it.
It also invites government interference and hackers.
Apple claims all of these features are done on the iDevice itself, and only activates them when you have iCloud backup enabled. You'll need to take Apple's word for that, however, I strongly recommend switching the iCloud off all together. It also keeps the question open, if you only scan when iCloud backup is enabled, why not just scan in the iCloud and leave our phones alone?
NOTE! Keep in mind, if iCloud backup is enabled (and it is by default) Apple has a key for all your devices, including the encryption key for iMessage.
To keep your iMessages scan free and your key in your hands, you have two options.
Option 1 — Disable iMessage
Settings — Apple ID — iCloud header — Disable iMessage by dragging the toggle from green to gray
Option 2 — Disable iCloud Backups
Settings — Apple ID — iCloud header — iCloud Backup header — Toggle the iCloud backup from green to gray — Confirm that you want to disable iCloud backup.
One more step!
Screen Time — Content & Privacy Restrictions — Privacy & Allowed Changes — Set all to “Don't Allow.”
This way you block Apple from resetting anything during a firmware update.
Just remember, iMessage is on every Apple device, so it is easy to communicate encrypted straight 'out of the box' without downloading another app. This said you cannot reach any Android, Linux, or Windows users. You have plenty of other better and safer options when it comes to secure and private messaging.
Yet again, the biggest question you need to ask yourself is "do I trust Apple?" and how heavily are you 'planted' in the Apple 'closed garden'? If you trust Apple and you are fine with Apple being able to scan your pictures, iMessage can be a good solution for you.