What technology can enhance a firewall's capabilities for secure web traffic?

Public Key Infrastructure (PKI) significantly enhances a firewall’s capabilities for secure web traffic by providing a framework for managing digital certificates and encryption keys. PKI enables secure communications over the internet through encryption, ensuring that sensitive data exchanged between clients and servers remains confidential and authenticated.

When integrated with a firewall, PKI allows for the management of secure sockets layer (SSL) or transport layer security (TLS) certificates, which are instrumental in establishing secure connections for web traffic. The firewall can use these certificates to inspect encrypted traffic without compromising security, enabling it to enforce security policies on both encrypted and unencrypted traffic. This capability is crucial as a large portion of web traffic today is encrypted, and traditional firewalls may struggle to inspect and manage this traffic effectively without the tools that PKI provides.

The other options do not directly enhance a firewall's capability for secure web traffic. Wi-Fi relates to wireless networking standards, VoIP focuses on enabling voice communication over the internet, and SMTP is a protocol for sending emails, none of which specifically address the encryption and certificate management needs for secure web traffic within a firewall context.