A security administrator needs to implement anX.509 solutionfor multiple sites within thehuman resources department. This solution would need tosecure all subdomainsassociated with thedomainnameof the main human resources web server. Which of the following would need to be implemented to properly secure the sites and provideeasier private key management?

Comprehensive and Detailed in-Depth Problem Statement: The security administrator needs a solution that: Securesmultiple subdomainsunder asingle domain name. Simplifiesprivate key management. UsesX.509 certificates, which are common forTLS/SSLin web environments. Why the Correct Answer is C (Wildcard certificate): AWildcard certificateallows thesame certificateto securemultiple subdomainsof a domain. The format for a wildcard certificate is usually: CopyEdit *.example.com This single certificate can cover: hr.example.com payroll.example.com benefits.example.com It significantlyreduces administrative overheadsince onlyone certificate and one private keyare needed. In anX.509 context, a wildcard certificate is commonly used forweb servers that host multiple subdomains. Key Benefits of Wildcard Certificates: Cost-Effective:One certificate forall subdomains. Simplified Management:Oneprivate keyto secure multiple services. Flexibility:Can addnew subdomainswithout issuing a new certificate. Compatibility:Widely supported inweb servers and application frameworks. Why the Other Options Are Incorrect:
A . Certificate revocation list (CRL): A CRL is used tolist revoked certificatesand ensure they are no longer trusted. It does notsecure multiple subdomainsormanage private keys.
B . Digital signature: A digital signature is used toverify the integrity and authenticityof data. It is not related tomanaging certificates or securing subdomains.
D . Registration authority (RA): An RA is responsible forvalidating identity and issuing certificates. It does not directly address theissue of securing multiple subdomains.
E . Certificate pinning: Certificate pinning ensures that an application only trustsspecific public keysto preventMitM attacks. It does not providemulti-subdomain supportorsimplify key management. Real-World Scenario: An organization runs anHR portalwith multiple subdomains: login.hr.example.com docs.hr.example.com support.hr.example.com Implementing awildcard certificateallows the company tomanage a single certificatewhile covering all these subdomains. This reduces themaintenance workloadsince updates or renewals only need to be performed onone certificate. Example of a Wildcard Certificate in Practice: Common Name (CN): CopyEdit *.hr.example.com Usage: Secures all subdomains within thehr.example.comnamespace. Reduces thenumber of certificates neededfrom one per subdomain to justone wildcard certificate. Visual Representation: lua CopyEdit +--------------------------+ | Wildcard Certificate | | (*.hr.example.com) | +--------------------------+ | +----------------+----------------+ | | hr.example.com payroll.hr.example.com | benefits.hr.example.com Asingle wildcard certificatecovers all subdomains underhr.example.com. Extract from CompTIA SecurityX CAS-005 Study Guide: TheCompTIA SecurityX CAS-005 Official Study Guideemphasizes thatwildcard certificatesare an efficient solution when securingmultiple subdomains under the same domain. They reduce the complexity ofprivate key managementand streamline thecertificate deployment process.