sertifikatkjede

A sertifikatkjede, Norwegian for “certificate chain,” is a sequence of digital certificates that link a website or application’s public key back to a trusted root certificate authority (CA). Each certificate in the chain is signed by the next certificate up the hierarchy, ending with a root certificate that is pre-installed in the user’s operating system or browser. The chain ensures that the authenticity and integrity of the public key can be verified by anyone who trusts the root CA.

The chain typically consists of three parts: the end‑entity certificate (the server or client), one or more intermediate certificates, and the root certificate. Intermediate certificates are issued by the root CA or other intermediates and provide a “bridge” that allows the root to delegate trust without exposing the root key to everyday usage. By limiting the use of the root key to issuing intermediates, PKI infrastructure reduces the risk of compromise.

During a TLS handshake, a server presents its sertifikatkjede. The client verifies each certificate by checking signatures, validity periods, and revocation status using CRLs or OCSP. If any link fails, the handshake is aborted, protecting users from man‑in‑the‑middle attacks and fraudulent certificates.

In blockchain and smart‑contract systems, a variant of the sertifikatkjede is used to certify the authenticity of identity registries, multisignature accounts, and digital asset ownership. Here, the certificates may be stored on-chain or referenced through hash pointers, ensuring that trust anchors can be audited by any network participant.

Overall, the sertifikatkjede is a foundational component of Public Key Infrastructure. It enables secure communication, authentication, and non‑repudiation across the internet and distributed systems by establishing a verifiable trust path to recognized certificate authorities.