Rich Communication Services

Rich Communication Services (RCS) is a communication protocol between mobile telephone carriers and between phone and carrier, aiming at replacing SMS messages with a text-message system that is richer, provides phonebook polling, and can transmit in-call multimedia. It is part of the broader IP Multimedia Subsystem. Google has added support for end-to-end encryption for all chats using RCS in their own app, Google Messages. End-to-end encryption is not a feature of RCS specified by GSMA.