Which of the following provides security by implementing authentication and encryption on Wireless LAN (WLAN)?

WEP was introduced as part of the original IEEE 802.11 standard specifically to provide confidentiality and access control on wireless networks through RC4 stream cipher encryption and shared-key authentication. It was designed to make the wireless medium as secure as a wired connection, giving rise to its name. Despite being deprecated due to known cryptographic weaknesses, WEP remains the answer here as the protocol explicitly built to deliver both authentication and encryption on WLANs.

WAP (Wireless Application Protocol) is a standard for accessing internet services on mobile devices and does not provide WLAN authentication or encryption.

L2TP (Layer 2 Tunneling Protocol) is a VPN tunneling protocol that itself provides no encryption - it relies on a companion protocol like IPSec for security and does not operate at the WLAN layer.

IPSec operates at the network layer (Layer 3) to secure IP communications and is not a WLAN-specific security mechanism - it does not address 802.11 authentication or wireless link encryption.