SRTP (Secure Real-time Transport Protocol)

Also known as: Secure RTP, RFC 3711

SRTP is the IETF profile of RTP (RFC 3711) that provides confidentiality, message authentication and replay protection for real-time media streams. In IMS, SRTP is used to protect voice and video media between UEs and SBCs, between SBCs at interconnect, and for Wi-Fi Calling. Key material is typically established via SDES in older deployments or DTLS-SRTP in modern ones. SRTP is complementary to signalling-plane protections such as SIP over TLS or IPsec.

Categories: Security ControlsProtocols and StandardsEncryption and Cryptography

SRTP in context

Security controls span signaling firewalls (SS7/Diameter/GTP screening), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how they interlock, is essential for both design and audit work.

To place SRTP in the wider telecom-security picture, review XMPP, DTLS-SRTP, NAF, HKDF, 3G and 6G — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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