SEPP (Security Edge Protection Proxy)

The Security Edge Protection Proxy is the 5G network function placed at the edge of every PLMN to terminate the N32 interface used for inter-operator signalling. It enforces application-layer protection (PRINS) that authenticates and integrity-protects each JSON message, optionally encrypting sensitive information elements end-to-end across IPX intermediaries. SEPP closes the inter-PLMN trust gap that plagued SS7 and Diameter, and is mandatory for any 5G operator offering or consuming roaming.

Categories: Core NetworkSignalingRoaming and Interconnect

SEPP in context

The mobile core carries subscriber sessions, mobility and policy. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF.

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.

To place SEPP in the wider telecom-security picture, review FS.07, FS.19, GGSN, GTP, GTP Firewall and HLR — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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