The key difference lies in the trust model. With private certificates, the company or operator of the private PKI determines which systems trust its CA. They are therefore particularly suitable for controlled enterprise and infrastructure environments.
Publicly trusted certificates, by contrast, are issued by Public CAs whose trust anchors are already included in widely used operating systems and applications. This means external systems can trust a certificate without first having to install the company’s own CA.
Many companies require both types of certificates in parallel. MTG CLM makes it possible to centrally manage private certificates from the company’s own PKI as well as certificates from connected Public CAs.