RCS (Rich Communication Services)

Rich Communication Services is the GSMA-defined IMS-based successor to SMS, providing read receipts, group chat, high-resolution media, and verified business messaging, accessed over Wi-Fi or mobile data. RCS is delivered over SIP/HTTP between the device and the operator's Messaging-as-a-Platform, frequently outsourced to a hyperscaler RCS hub. Security challenges include account takeover via the device's MSISDN binding, end-to-end encryption only being added in recent revisions, and impersonation of unverified senders.

Categories: SignalingIdentity and SubscriberSecurity Controls

RCS in context

Signaling protocols carry the control-plane messages that set up calls, register subscribers and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA as top-tier telecom risk.

Subscriber identifiers (IMSI, SUPI, MSISDN, IMEI) anchor authentication, charging and lawful interception. Any protocol that leaks a permanent identifier is treated as a privacy defect, which is why 5G introduced SUCI concealment on the air interface.

To place RCS in the wider telecom-security picture, review AAA, Any-Time Interrogation (ATI), CAP, IMSI, STIR and 1G — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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