A security analyst is hardening a web server, which should allow a secure certificate-based session using the organization's PKI infrastructure. The web server should also utilize the latest…

X.509 is the standard certificate format used by PKI infrastructures, defining the structure for public key certificates, including fields for the issuer, subject, validity, and public key; installing an X.509-compliant certificate ensures compatibility with the organization's PKI and enables certificate-based authentication.

A Certificate Revocation List (CRL) is a mechanism to check whether certificates have been revoked, but implementing a CRL alone does not establish secure certificate-based sessions or fulfill the requirement for the latest security techniques on the web server itself.

TLS (Transport Layer Security) is the current industry-standard protocol for securing web communications, replacing the deprecated SSL; enabling and configuring TLS on the server ensures encrypted sessions using the latest security techniques and satisfies the requirement for modern standards.

Installing a certificate signed by a public CA contradicts the requirement to use the organization's own PKI infrastructure, as public CAs are external third-party authorities rather than the internal organizational PKI.

A host header is an HTTP configuration used to support multiple virtual hosts on a single IP address and has no bearing on certificate-based security, PKI integration, or modern security standards.