OCSP (Online Certificate Status Protocol)

The Online Certificate Status Protocol (RFC 6960) lets a client check whether an X.509 certificate has been revoked by querying a responder run by the issuing CA, returning a signed status. OCSP is faster and less bandwidth-intensive than downloading full CRLs but introduces availability and privacy concerns, mitigated by OCSP Stapling (RFC 6066) where the server presents the response.

Categories: Security ControlsProtocols and StandardsRegulation and Compliance

OCSP in context

Security controls in telecom span signaling firewalls (SS7/Diameter/GTP screening at the network edge), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both the packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36 and, in Europe, NIS2 sectoral rules.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how the specs interlock (for example 3GPP TS 33.501 with GSMA FS.34 for 5G SBA security), is essential for both design and audit work.

To place OCSP in the wider telecom-security picture, review EAP, OSPF, TR-069, DTLS-SRTP, 3G and Digital Signature.

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