ocspd:tldr:4fada

ocspd is a command in macOS that stands for "Online Certificate Status Protocol daemon". It is responsible for handling the Online Certificate Status Protocol (OCSP) requests and providing certificate revocation status information.

The OCSP protocol is used as an alternative to Certificate Revocation Lists (CRLs) for checking the validity of digital certificates. When a client needs to verify the status of a certificate (e.g., checking if it has been revoked), it sends a request to an OCSP server. The ocspd daemon on macOS acts as a local OCSP responder, which means it can handle these requests internally without the need to connect to an external OCSP server.

The ocspd command starts and manages the ocspd daemon on macOS. It runs as a background process and listens for incoming OCSP requests on the local machine. The daemon is responsible for fetching and caching certificate revocation information from the appropriate OCSP servers, and responding to client requests based on that information.

Using the ocspd command, system administrators can control the behavior and configuration of the ocspd daemon, such as specifying the OCSP servers to use, cache settings, logging options, etc.

Overall, ocspd is a vital part of macOS's security infrastructure, ensuring that digital certificates are valid and trusted by verifying their status through the OCSP protocol.