nline ertificate tatus rotocol A simple request/reply protocol that allows clients to ask an "OCSP responder" about the revocation status ofone or more certificates. The OCSP responder returns digitally signed responses regarding the status of the certificates identified in the request. (Other protocols are being worked-on and OCSP may be soon overtaken).

A protocol used to track certificate revocation status in public-key infrastructure (PKI) security. See PKI.

Online Certificate Status Protocol. A set of rules that Certificate Manager follows to perform an online check of a certificate's validity each time the certificate is used. This process involves checking the certificate against a list of valid certificates maintained at a specified web site. Your computer must be online for OCSP to work.

Online Certificate Status Protocol. A dynamic method of checking to ensure the validity of a certificate. OCSP defines queries by which a client can ask a Certificate Authority (CA) the status of a certificate it has received. The CA replies that it is either valid, invalid, revoked, not revoked or expired. OCSP eliminates the need to manually maintain and match a local list of revoked certificates with the Certificate Revocation List maintained on the Certificate Authority.