Issuer

The Issuer field in an SSL certificate identifies the Certificate Authority (CA) that issued and digitally signed the certificate. This field contains the Distinguished Name (DN) of the CA, including information such as the organization name, country, and sometimes organizational unit. The issuer is crucial for establishing the chain of trust - browsers maintain a list of trusted root CAs, and they verify that the certificate was signed by a trusted authority. Popular issuers include DigiCert, Let's Encrypt, GlobalSign, Sectigo (formerly Comodo), and GeoTrust. The issuer's reputation and trustworthiness directly affect how browsers and users perceive the certificate. When a certificate is validated, the browser checks the entire certificate chain from the end-entity certificate up to a trusted root CA, and the issuer field helps establish this chain of trust.

Untrusted or mis-issued certificates from the wrong issuer can cause Cloudflare Error 526.