Which of the following authentication methods are supported in an IPsec phase 1? (Choose two.)

While RSA signature authentication uses asymmetric key cryptography, 'Asymmetric Keys' is a broad cryptographic concept rather than a specific, named authentication method directly configured in IPsec Phase 1.

CA root digital certificates are essential for establishing the trust chain when using certificate-based authentication (like RSA signatures), but they are not the authentication *method* itself; they enable the trust in the peer's certificate.

RSA signature authentication is a method used in IPsec Phase 1 where peers authenticate by signing data with their private RSA key, verifiable by the other peer's public key obtained from a digital certificate.

Pre-shared keys (PSK) are a common and straightforward authentication method for IPsec Phase 1, requiring both communicating peers to be configured with the exact same secret key.