Which of the following is needed to securely distribute symmetric cryptographic keys?

PKI Class 3/4 certificates are used for asymmetric (public-key) infrastructure to validate identities and establish trust, not specifically for distributing symmetric keys.

Symmetric key distribution requires formally approved key management technology and processes because symmetric keys must be securely generated, stored, distributed, and destroyed without exposure. Compliance with standards such as NIST SP 800-57 ensures that the key management lifecycle - including secure key exchange mechanisms like key wrapping or key agreement protocols - is handled in a controlled, auditable manner that prevents unauthorized disclosure.

A communication protection policy and key management plan are organizational governance documents, but alone they do not constitute the technical technology and approved processes needed to actually distribute symmetric keys securely.

Hardware tokens protect a user's private key in asymmetric cryptography scenarios, not for the distribution of symmetric cryptographic keys shared between parties.