You are concerned about war driving bringing hackers attention to your wireless network. What is the most basic step you can take to mitigate this risk?

WEP (Wired Equivalent Privacy) is a deprecated encryption protocol with well-documented cryptographic weaknesses that can be cracked in minutes, making it an ineffective security control and not the most basic mitigation for war driving visibility.

MAC filtering restricts which devices can associate with an access point, but the network SSID remains visible in beacon frames, so it does not reduce war driving visibility and MAC addresses can be spoofed.

War driving relies on passive scanning tools that detect beacon frames containing the SSID broadcast by access points; suppressing the SSID broadcast means the network will not appear in these passive scans, reducing its visibility to opportunistic attackers. While this is considered security through obscurity and a determined attacker can still discover the network through active probing, it is the simplest and most immediate mitigation step. It requires no additional hardware or complex configuration changes.

WPA provides strong encryption and authentication, which is a more complex configuration change and addresses data security rather than directly reducing network visibility to war drivers performing passive scans.