A security administrator is tasked with implementing two-factor authentication for the company VPN. The VPN is currently configured to authenticate VPN users against a backend RADIUS server. New…

A user's private key must remain exclusively under that user's control and must never be copied to the VPN concentrator; distributing it would compromise the entire premise of asymmetric PKI security.

The CA's private key is the most sensitive asset in a PKI and must never leave the CA infrastructure; installing it on the VPN concentrator would represent a catastrophic security compromise.

In PKI, it is the certificate (the document containing the public key) that is digitally signed by the CA - not the private key; private keys are generated locally and are never signed by any authority.

While the VPN concentrator's certificate is correctly signed by the CA, the option incorrectly states that the private key is signed by the CA; the private key is never signed, and only the certificate containing the corresponding public key receives the CA signature.

The VPN concentrator must have its own certificate's private key installed locally so it can perform the cryptographic operations required to authenticate itself to connecting VPN clients during the TLS/SSL handshake.

Installing the CA's public certificate (root or intermediate CA cert) on the VPN concentrator enables it to verify the chain of trust for user certificates presented during authentication, preventing untrusted certificate error messages from appearing to users.