Source

• WEP received its name because it was the first security protocol officially accepted as part of Wireless local area networks (LANs). A non-wireless LAN may be physically secure because it is in a building with doors and locks and security guards and data travelling on it is inside a cable. Wireless signals can transmit data through walls and beyond any physical controls. The encryption design for wireless methods attempted to ensure the same level of privacy for data on a Wireless LAN as on a wired LAN, hence, "Wired Equivalent Privacy."
  
  

Function

• WEP is implemented on the wireless Network Interface Card (NIC). Before transmitting the data in packets, the NIC encrypts the packet body with an RSA cypher.
  
  

Drawbacks

• Weaknesses were discovered in WEP's procedures enabling signals to be intercepted. WEP was dropped as a recommended standard for Wireless LAN security and was replaced by "Wi-Fi Protected Access" (WPA).