802.11 Security

WEP

Interception of radio communications has been a problem for as long as radios have been used to transmit sensitive information. Radio-based communication can be used to transmit instructions to troops during warfare, credit-card info from a cell phone, or passwords from a laptop to a remote web site. Since radio transmissions travel in unsecured areas, interception of these radio signals by an attacker is a real threat. In order to protect the data from eavesdroppers, various forms of encryption have been used to scramble the data. Sometimes these encryption mechanisms have been successful; other mechanisms have been compromised, thereby subverting the security of the data.

The 802.11 MAC specification describes an encryption protocol called Wired Equivalent Privacy (WEP). The goal of WEP is to make WLAN communication as secure as wired LAN data transmissions would be. If WEP were to meet this goal, it would allow network architects to deploy wired and wireless LANs interchangeably without regard to different security risks.

WEP provides two critical pieces to the wireless security architecture: authentication and confidentiality. WEP uses a shared key mechanism with a symmetric cipher called RC4. The key that a client is using for authentication and encryption of the data stream must be the same key that the AP uses. The 802.11 standard specifies a 40-bit key, however most vendors have also implemented a 104-bit key for greater security.

Encryption

Encryption of the data ...