OCSPCRLtarkistus

OCSPCRLtarkistus is a Finnish term that translates to "OCSP CRL check" or "OCSP and CRL check" in English. It refers to a security process used in the context of digital certificates. This process involves verifying the status of a digital certificate using two primary methods: the Online Certificate Status Protocol (OCSP) and Certificate Revocation Lists (CRLs).

OCSP is a real-time protocol used to obtain the revocation status of a digital certificate. When a client needs to verify a certificate, it sends an OCSP request to a designated OCSP responder. The responder then replies with a signed status message indicating whether the certificate is valid, revoked, or unknown. This method provides a more immediate status update compared to CRLs.

CRLs, on the other hand, are lists published by Certificate Authorities (CAs) that contain serial numbers of certificates that have been revoked. Clients can download these lists and check them to see if a particular certificate appears. CRLs are typically updated periodically, meaning there can be a delay between a certificate's revocation and its appearance on the list.

Therefore, OCSPCRLtarkistus encompasses the combined use of both OCSP and CRLs to ensure the trustworthiness of a digital certificate. This dual approach provides a more robust and comprehensive verification mechanism, as it allows for both real-time status checks through OCSP and broader checks through periodically updated CRLs. The goal is to prevent the use of certificates that are no longer considered valid due to compromise, expiry of the CA, or other reasons.