Certum will start issuing SSL/TLS certificates from dedicated TLS Root CAs

Starting from January 2027, Certum plans to start issuing public SSL/TLS certificates from two Root CAs dedicated to TLS:

• Certum TLS RSA Root CA
• Certum TLS ECC Root CA

These are new Root CAs that are being introduced into browser and operating system Root Store Programs. As a result, trust in these Root CAs will be established progressively across different browsers, operating systems and other platforms.

During this transition period, customers will need to use the appropriate cross-certificate as part of the certificate chain to ensure that systems which do not yet directly trust the new Root CAs can build a valid trust path to an already trusted Root CA.

Additionally, for newly issued SSL/TLS certificates from the dedicated TLS hierarchy, they will not contain the clientAuth Extended Key Usage (EKU). They will be intended for TLS server authentication only.

Certificates that have already been issued will not change and will remain valid until their expiration date.

Why is Certum introducing new TLS Root CAs?

The introduction of Certum TLS RSA Root CA and Certum TLS ECC Root CA is part of a broader transition of Certum’s PKI infrastructure to new, dedicated Root CA hierarchies.

Requirements for publicly trusted certificate hierarchies continue to evolve. Browser and Root Store Programs are moving towards dedicated PKI hierarchies in which Root CAs are used for specific purposes, such as TLS server authentication.

The new Certum TLS RSA Root CA and Certum TLS ECC Root CA are dedicated specifically to Certum’s public SSL/TLS certificate hierarchy. Their introduction allows Certum to align its infrastructure with current Root Store Program requirements and to separate TLS certificate issuance from other certificate use cases.

For more information about Certum’s broader transition plan for the new Root CAs, see:
https://bugzilla.mozilla.org/show_bug.cgi?id=2030937

What does this change mean for me?

For most users, the change will not require any immediate action.

If you already have a valid Certum SSL/TLS certificate, it will not be modified or replaced as a result of this change. It will remain valid until its expiration date.

Once Certum starts issuing certificates from the new TLS hierarchy, newly issued SSL/TLS certificates will chain to Certum TLS RSA Root CA or Certum TLS ECC Root CA.

This change will apply equally to the activation of new products as well as to situations where, using the reissue process, you obtain another certificate within a previously ordered product.

Because these Root CAs are still gaining trust across browsers, operating systems and other platforms, the certificate chain provided with your certificate will use an appropriate cross-certificate where required. This enables systems that do not yet trust the new Root CA directly to build a valid trust path to an already trusted Root CA.

When installing a newly issued certificate, it is therefore important to use the complete certificate chain provided for that certificate.

What will change for Client Authentication and mTLS?

This is an important change if you currently use a public Certum SSL/TLS certificate for Client Authentication or mutual TLS (mTLS).

New SSL/TLS certificates issued from the dedicated Certum TLS hierarchy will not contain the clientAuth Extended Key Usage (EKU). They will be intended for TLS server authentication only.

This means that a newly issued certificate from the new hierarchy should not be expected to work as a client certificate in an mTLS configuration that requires the clientAuth EKU.

If your infrastructure uses the same public SSL/TLS certificate for both server authentication and Client Authentication, you should prepare to use a separate certificate intended for Client Authentication.

Who may be affected by this change?

Most customers using Certum SSL/TLS certificates for standard HTTPS server authentication should not experience disruption, provided that the complete certificate chain is correctly configured.

The change will require action from you if:

• you use Certum public SSL/TLS certificates for Client Authentication or mTLS;
• your infrastructure uses certificate, public key or CA pinning, or otherwise expects a specific Certum Root CA or certificate chain;
• you maintain a custom trust store rather than relying on the trust store provided and updated by the operating system, browser or runtime;
• your systems run on older or no longer updated platforms whose trust stores may not receive updates for the new Certum TLS Root CAs;
• your application contains a hard-coded Root CA, intermediate CA or expected certificate chain, which may prevent it from accepting a certificate issued from the new hierarchy.

Cross-certification is intended to maintain compatibility while the new Root CAs gain broader trust. However, systems that restrict trust to a specific CA, certificate, public key or fixed certificate chain may require configuration changes.

Do I need to take any action?

If you use Certum SSL/TLS certificates only for standard HTTPS and your systems use current, regularly updated trust stores, no immediate action is required.

If any of the scenarios described above apply to your environment or application, we recommend reviewing your configuration before installing a certificate issued from the new TLS hierarchy. In particular, make sure that your systems can use the required certificate chain and do not rely on the clientAuth EKU or on a specific Certum CA or certificate chain.

Certum plans to start issuing its standard SSL/TLS certificates from Certum TLS RSA Root CA and Certum TLS ECC Root CA starting from January 2027. The transition to the new TLS hierarchy will be gradual. If a certificate is issued from the new root, along with the certificate issuance notification Certum will send a reminder about the need to use the full, correct certificate chain.

Certificates required to build the full certificate chain can be downloaded from the Certum website: https://www.certum.eu/en/cert_expertise_root_certificates/

We will update this announcement as more detailed information about the introduction of the new TLS Root CAs becomes available.