tanúsítványláncot

Tanúsítványlánc refers to a sequence of digital certificates used in cryptography and security. Typically, this chain starts with a user's or server's end-entity certificate and extends upwards through one or more intermediate certificates to a trusted root certificate. Each certificate in the chain, except for the root, is signed by the certificate that precedes it in the sequence.

The primary purpose of a tanúsítványlánc is to establish trust. When a client (like a web browser) receives an end-entity certificate, it verifies the signature on that certificate using the public key of the issuing intermediate certificate. This process is repeated up the chain until the client reaches a root certificate that is already present in its trust store. If all signatures in the chain are valid and the root certificate is trusted, the end-entity certificate is considered trustworthy.

This hierarchical structure allows for efficient management of certificates. Instead of every client needing to trust every single issuing authority, they only need to trust a limited number of well-known root Certificate Authorities (CAs). The intermediate CAs can then be managed by the root CAs, delegating the task of issuing end-entity certificates.

Tanúsítványlánc validation is a critical step in secure communication protocols like TLS/SSL, ensuring that the parties involved are who they claim to be. If any certificate in the chain is invalid, expired, or cannot be traced back to a trusted root, the connection is typically flagged as insecure.