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RCS chat: a better SMS for Android?

Posted on January 7, 2020

Android has started rolling out Rich Communication Services (RCS) chat features to users of its Messages app, touting this as a better, more up-to-date successor to traditional SMS texting. However, there is still some confusion about what RCS is — and how it’s different from SMS. In this short article, we’ll cover the basics of RCS and let you know what it means for you (even if you’re a dedicated iPhone user).

Why RCS matters

RCS is important because it’s going to affect most of the world’s mobile phone users: Android operating systems power approximately 75% of all mobile devices worldwide. So even if you have an Apple device, you’re likely living and working alongside a far greater number of Android users who will now be relying on RCS to send texts. Additionally, many iOS and Mac devotees are cross-platform users who own Android devices as well — either by choice or due to workplace requirements. Lastly, as we’ll see toward the end of this article, iOS users may one day see an Apple implementation of RCS, depending on how the company decides to deal with external pressure to support the new communication protocol.

What was wrong with SMS?

SMS, which stands for “Short Message Service”, has been around since the early 90’s, and the world of mobile device use has changed tremendously since then.

The drawbacks of SMS — character and file size limits, lack of read receipts, minimal support for multimedia files — are no longer acceptable to the majority of mobile users. Cellular carriers also offer MMS (short for “Multimedia Messaging Service”), which extends the functionality of SMS and allows users to send multimedia files, but even MMS lags far behind the modern third-party messaging apps that most people have grown accustomed to. In addition, SMS is notoriously insecure, because it doesn’t provide end-to-end encryption — leaving the contents of messages visible to cellular carriers, governments, and hackers. 

While third-party messaging apps like WhatsApp and Signal solve many of these problems, they lack the ability of SMS to provide a universal messaging system, because they don’t offer the cross-compatibility of SMS: You can’t use WhatsApp to send a message to someone using Signal; companies can’t use Telegram to send messages to their customers if those customers aren’t also using Telegram.

How does RCS solve (some of) these problems?

RCS is meant to provide a far better user experience than SMS, while still working on all devices and platforms. It will have features like read receipts and location sharing, support for large multimedia files, and group chat. 

RCS works with a data or a WiFi connection, meaning that it can be used even when cellular service is unavailable. It also supports sender verification for organizations and brands, making it harder for malicious actors to use phishing texts to impersonate a well-known company.

Who is behind RCS?

It should be noted that RCS is a communications protocol developed and supported by many players within the world of mobile communications. RCS has been developed and standardized by a steering committee at the GSMA, the trade body representing the world’s mobile operators. 

Google has been a big backer of RCS, and is the driving force behind the recent wide-scale rollout of RCS messaging in the United States. But the Android version of RCS, RCS chat for Messages, is just one of many implementations of RCS — phone manufacturers like Samsung, for example, have their own native RCS messaging offerings. 

The RCS chat functionality now coming to Android’s Messages app is, however, especially important, as it makes RCS messaging available to a huge number of users all at once. This will speed up the adoption of RCS and put pressure on slower-moving manufacturers and telcos to catch up.

What’s wrong with RCS?

Like everything, RCS has its limitations.

First of all, there is the issue of security. RCS does not provide end-to-end encryption, unlike popular messaging apps such as Signal, WhatsApp, Telegram, and (at least when used between two Apple devices) iMessage. 

In addition, security researchers have raised concerns about how the RCS protocol is being implemented by some mobile carriers, saying that poor security practices are already exposing users to potential attacks (this isn’t an issue with RCS itself, but rather how it’s being used).

Lastly, RCS is not currently supported by Apple: iMessage is based on a different communication protocol than SMS, MMS, or RCS. You can still use iMessage to communicate with someone who is using an Android phone, of course, but your device won’t be able to use the RCS protocol to do so: It will simply fall back on its “plan B” and treat the other person’s messages as SMS or MMS (you’ll see their texts appear in a green bubble to let you know that your communications are unencrypted).

The future of RCS

As more mobile carriers work out the bugs and figure out how to implement RCS securely (or at least, as securely as possible), RCS will become a fuller-featured successor to SMS.

But it’s an open question as to when — or if — Apple will provide support for RCS. There have been vague reports of Apple being “in discussions” about bringing RCS to iOS, as well as mentions of mobile operators “putting pressure” on Apple to do so, but all of these seem to be based on a single presentation slide from a GSMA industry event, and Apple is well known for marching to the beat of its own drum.

It’s also doubtful that anything like iMessage’s end-to-end encryption will ever come to RCS, due in part to legal and political pressures on carriers to keep customer data available to law enforcement agencies and governments if requested as part of a criminal investigation.

In short, Android users should enjoy the new functionality provided by RCS chat, whether they’re using the Android Messages version or some other implementation, but they shouldn’t consider it any more secure than traditional SMS or MMS. Apple users should realize that, at least for now, they’re still going to be limited to SMS/MMS texting with their Android-using friends. And all mobile device users who want private, secure communications should continue to rely on third-party messaging apps which offer default end-to-end encryption.

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