Rich Communication Services

What Is RCS?

The video above by popular tech YouTuber TheUnlockr (David Cogen) explains what RCS is. Though this video was published in 2019 and some things about RCS have since changed (like that Apple has recently announced they will support RCS), the video does a good job explaining the basics.

Though RCS has become a more popular form of messaging over the past few years, it actually was proposed back in 2007. It was not until Google began leading the development of RCS that it gained more traction. As you’ve learned about now, SMS and MMS are both rather limited in their capabilities, and it was known soon after their creation that improvements should be made. It took some time, but as of 2023, most major carriers support RCS. There is a Universal standard of RCS, while Google has its own version. The two standards are compatible, but only Google’s supports end to end encryption (E2EE, which you can learn more about in our cryptography section). Though the RCS Universal Standard lacks end-to-end encryption for now, it does support the features that SMS/MMS lack like longer messages, high-resolution photos and videos, read receipts, typing indicators, group chats, reactions, and more.

Apple announced in November 2023 that they would be supporting the universal standard of RCS, which is good news for people who message between iPhone and Android phones. RCS will likely never be a total replacement for third-party messaging services, but the future is bright for RCS and it certainly accomplished its mission of improving upon its predecessors SMS and MMS

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How Secure is RCS?

When using RCS, the security of your messaging can depend on the specific messenger app you're using. As discussed above, Google’s standard of RCS supports end to end encryption, but the universal standard does not. If you’re using Google’s messaging app and messaging another person using Google’s messaging app, you will have E2EE by default (only as of August 2023 did Google decide to make E2EE the default option). Google Messages users won’t get E2EE when exchanging RCS messages with someone using a non-Google RCS messaging app, unless the app adopts Google’s unique extensions of RCS.

Apple will only support RCS Universal Standard and not Google’s extension, meaning no end-to-end encryption between iPhones and Android phones will be available until the Universal Standard supports E2EE. Despite this, Apple has stated they plan to work with the GSMA to add more encryption to the RCS universal standard. Without E2EE, RCS messaging, like SMS and MMS, can be susceptible to attacks. The information in your messages could be stored in your cellular provider’s system. This means it could be viewed by the cell provider, and could be stolen if someone hacks into the cell provider’s system.

For the most privacy, when using RCS, we recommend using an app that supports a standard withe end-to-end encryption, like Google Messages.

Data Privacy in Messaging
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