science

IMessage

IMessage is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand IMessage rather than just read about it. In short: iMessage is an instant messaging service developed by Apple and launched on October 12, 2011. iMessage functions exclusively on Apple platforms, including iOS, iPadOS, macOS, watchOS, and visionOS. iMessage uses the Messages app client. Core features of iMessage include sending text messages, images, videos, and arbitrary files to individual recipients and group chats; getting delivery and read statuses (read receip…

Key takeaways

IMessage belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IMessage to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IMessage from memory before moving on to harder problems.

Reference excerpt

iMessage is an instant messaging service developed by Apple and launched on October 12, 2011. iMessage functions exclusively on Apple platforms, including iOS, iPadOS, macOS, watchOS, and visionOS. iMessage uses the Messages app client. Core features of iMessage include sending text messages, images, videos, and arbitrary files to individual recipients and group chats; getting delivery and read statuses (read receipts); and end-to-end encryption so only the sender and recipient can read the messages. The service also allows sending location data and stickers. On iOS and iPadOS, third-party developers can extend iMessage capabilities with custom extensions. iMessage was introduced with iOS 5 in 2011, and added to Macs with OS X Mountain Lion in 2012. In 2020, Apple introduced a redesigned Mac version of the Messages app with macOS Big Sur, adding some of the features previously unavailable on the Mac, such as location sharing and message effects.

History iMessage was announced by Scott Forstall at the WWDC 2011 keynote on June 6, 2011. A version of the Messages app for iOS with support for iMessage was included in the iOS 5 update on October 12, 2011. On February 16, 2012, Apple announced that a new Messages app would be part of OS X Mountain Lion, replacing iChat, and released a beta version of the Messages app the same day. Mountain Lion was released on July 25, 2012. On October 23, 2012, Apple CEO Tim Cook announced that Apple device users had sent 300 billion messages using iMessage and that Apple delivered an average of 28,000 messages per second. In February 2016, Eddy Cue announced that the number of iMessages sent per second had grown to 200,000. In May 2014, a lawsuit was filed against Apple over an issue where, if a user switched from an Apple device to a non-Apple device, messages being delivered to them through iMessage would not reach their destination. In November 2014 Apple addressed this problem by providing instructions and an online tool to deregister iMessage. A federal court dismissed the suit in Apple's favor. On March 21, 2016, a group of Johns Hopkins University researchers published a report in which they demonstrated that an attacker in possession of iMessage ciphertexts could decrypt photos and videos that had been sent via the service. The researchers published their findings after Apple had patched the vulnerability. On June 13, 2016, Apple announced the addition of Apps to the iMessage service, accessible via the Messages apps. Apps can create and share content, add stickers, make payments, and more within iMessage conversations without having to switch to standalone apps. One could develop standalone iMessage apps or an extension to existing iOS apps. Publishers can also create standalone stickers apps without writing any code. According to Sensor Tower, a data company that provides app store optimization services, as of March 2017 the iMessage App Store featured nearly 5,000 Message-enabled apps. At the WWDC 2020 keynote on June 22, 2020, Apple previewed the next version of its macOS operating system, planned for release in late 2020. Big Sur shipped with a redesigned version of Messages, with features previously available only on iOS devices, such as message effects, memoji, stickers and location sharing. On February 21, 2024, Apple announced that it would upgrade the iMessage protocol with a new post-quantum cryptographic (PQC) protocol called "PQ3". Apple said that, although quantum computers do not yet exist, it wanted to mitigate risk from future quantum computers as well as so-called "Harvest now, decrypt later" attack scenarios. Apple said it believed its PQ3 implementation provides protections that "surpass those in all other widely deployed messaging apps". Furthermore, because, according to Apple, there is no standard on security properties for messaging security levels that allow for easy comparison, Apple decided to create its own definitions consisting of 4 levels between 0 and 3. On this scale, Apple considers its PQ3 protocol to have "Level 3 security". The main differentiator of PQ3 compared to other PQC protocols is that it uses ongoing keying. Apple rolled out PQ3 with the public release of iOS 17.4, iPadOS 17.4, macOS 14.4, and watchOS 10.4, saying, "iMessage conversations between devices that support PQ3 are automatically ramping up to the post-quantum encryption protocol" and that PQ3 "will fully replace the existing protocol within all supported conversations [in 2024]."

Digital Markets Act (European Union)

In 2022, iMessage was included on a list of potential "gatekeeper services" to be regulated by new legislation in the European Union. This would have required iMessage to be interoperable with other messaging services that either serve a certain number of users or generates significant revenue. In September 2023, the Financial Times reported based on two sources with direct knowledge on the matter, that Apple appealed the inclusion of iMessage on the grounds that the iMessage userbase in Europe was not large enough to warrant labeling iMessage as a gatekeeper service. In December 2023, several media outlets reported that the appeal was successful. Bloomberg speculated that this "tentative" decision was reached because while iMessage's userbase is large enough to qualify, the service is not popular enough with businesses, specifically. This rumored tentative decision was later formalized on February 13, 2024, when the European Commission announced that they had decided that, together with Bing, Edge and Microsoft Advertising, iMessage does not qualify as gatekeeper services. The European Commission did not go into detail on their decision beyond stating that it was the result of "a thorough assessment of all arguments, taking into account input by relevant stakeholders, and after hearing the Digital Markets Advisory Committee." Despite the lack of detail provided by the European Commission on their decision, multiple outlets speculated that the decision was indeed based on iMessage not meeting the threshold necessary to be classified as a gatekeeper service as was reported in the prior year. This ultimately meant that Apple didn't have to make iMessage interoperable with other messaging services, nor did Apple have to conform to the other DMA regulations insofar it pertained to iMessage.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with IMessage

Start with the simplest possible case. Write down what IMessage claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to IMessage before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about IMessage ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of IMessage

In research: IMessage appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses IMessage in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: IMessage is common in secondary-school and first-year university syllabi. It links to neighbouring topics End-to-end encryption, Instant messaging protocols, so understanding it makes those chapters shorter.
In everyday life: Look for IMessage outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study IMessage in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IMessage means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain IMessage out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IMessage in simple terms?

Why does IMessage matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study IMessage?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on IMessage.