...
This CA has cross-signed a previously intermediate CA certificate as its own root certificate in 2020. This leads to a new, shorter, CA chain path stopping at the root variant of "USERTrust RSA Certificate Authority". The older CA chain path with a CA of that same name as an intermediate variant, and a root CA certificate named "AAA Certificate Services" continues to be offered by Sectigo only for compatibility with very old legacy systems which are unaware of the root variant of USERTrust. It is NOT RECOMMENDED to download and use the longer chain as Windows 10 has known issues building a trusted path when the USERTrust CA happens to be installed as a root variant already (which becomes increasingly common over time). Identity Providers using certificates from this CA should NOT include the intermediate CA variant of "USERTrust RSA Certificate Authority" in their onboarding tool and EAP server configurations. All contemporary supplicants include this CA as a root CA and can build a trust chain with it.
In summary:
- The RADIUS/EAP server should send the server certificate and the intermediate(s) below USERTrust RSA Certification Authority. This is typically only one intermediate certificate with names "GEANT OV RSA CA 4" or "Sectigo RSA Organization Validation Secure Server CA"
- When using eduroam CAT as the onboarding tool, include only the root variant of USERTrust RSA Certificate Authority
Consideration 2: Recommended certificate properties
...