Certificate Chain

The ordered sequence of certificates that links a server's leaf certificate back to a trusted root CA. A typical chain is: leaf certificate → one or more intermediate CA certificates → root CA certificate. Browsers validate the chain by checking signatures at every step; a missing or incorrect intermediate certificate causes an SSL_ERROR_BAD_CERT_DOMAIN or UNABLE_TO_VERIFY_LEAF_SIGNATURE error. Servers should always send the full intermediate chain alongside their own certificate to ensure clients can verify it without additional lookups.