Final answer:
A certificate chain, also known as a certificate path, is a series of certificates used to verify the authenticity and integrity of a digital certificate. It consists of a root certificate, intermediate certificates, and an end-entity certificate. The chain is checked by web browsers or software clients to ensure that the certificate has been issued by a trusted certificate authority.
Step-by-step explanation:
A certificate chain, also known as a certificate path, is a series of certificates that are used to verify the authenticity and integrity of a digital certificate. In the context of computer security, a digital certificate is a cryptographic document that binds the identity of a person or organization to a public key. The certificate chain consists of a root certificate, intermediate certificates, and an end-entity certificate.
When a web browser or other software encounters a website or service with a digital certificate, it checks the certificate chain to ensure that the certificate has been issued by a trusted certificate authority (CA). The root certificate is the topmost certificate in the chain and is issued by a trusted CA. Intermediate certificates are issued by the root certificate or other intermediate certificates in the chain. The end-entity certificate, also known as the leaf certificate, is the certificate issued to the entity (e.g. website) being authenticated.
By examining the certificate chain, a software client can verify that the end-entity certificate is trustworthy and has not been tampered with. If any of the certificates in the chain are invalid, expired, or not recognized, the software client will display a warning or error message to the user. This verification process helps ensure that the communication between a user and a website or service is secure and that the user is not interacting with an imposter or malicious entity.