OCSPprotokolle

OCSP (Online Certificate Status Protocol) is a protocol used to determine the revocation status of digital certificates. It is defined in RFC 6960 and is widely used in public key infrastructure (PKI) to ensure the validity of certificates. OCSP operates over HTTP or HTTPS and allows clients to query a designated OCSP responder to check the status of a certificate without needing to download and process the Certificate Revocation List (CRL).

The OCSP protocol involves a client sending a request to an OCSP responder, which then responds with the current status of the certificate. The status can be one of the following: good, revoked, or unknown. The responder typically caches the status of certificates to improve performance and reduce the load on the certificate authority (CA).

One of the key advantages of OCSP is its real-time nature, as it provides up-to-date information on the certificate's status. This is particularly important for applications that require immediate verification of certificate validity, such as secure web transactions. However, OCSP does have some limitations, including potential latency issues and the need for reliable network connectivity.

OCSP is often used in conjunction with CRLs to provide a more comprehensive revocation mechanism. While CRLs provide a list of revoked certificates, OCSP offers a more efficient and timely method for checking the status of individual certificates. This dual approach helps ensure that digital certificates remain a reliable and secure method of authentication and encryption in various online transactions.