The intermediate certificate works as a substitute for the root certificate. CAs keep the keys of the root certificate secret to hide from attackers and use the intermediate certificate to sign SSL certificates. If the root certificate is compromised, the whole certificate structure will be useless. An intermediate certificate is placed between the root certificate and the issued SSL certificate. Thus, it creates a chain of trust that starts from the root certificate, travels through an intermediate certificate, and ends its cycle with an issued SSL certificate.