IEEE 802.11 standard
A family of standards that defines the physical layers (PHY) and the Media Access Control (MAC) layer.
* IEEE 802.11a: 54 Mbps in the 5.7 GHz ISM band
* IEEE 802.11b: 11 Mbps in the 2.4 GHz ISM band
* IEEE 802.11g: 54 Mbps in the 2.4 GHz ISM band
* IEEE 802.11i: security. The IEEE initiated the 802.11i project to overcome the problem of WEP (which has many flaws and it could be exploited easily)
* IEEE 802.11e: QoS
* IEEE 802.11f: Inter Access Point Protocol (IAPP)
More information about 802.11i:
The new security standard, 802.11i, which was ratified in June 2004, fixes all WEP weaknesses. It is divided into three main categories:
1. Temporary Key Integrity Protocol (TKIP) is a short-term solution that fixes all WEP weaknesses. TKIP can be used with old 802.11 equipment (after a driver/firmware upgrade) and provides integrity and confidentiality.
2. Counter Mode with CBC-MAC Protocol (CCMP) [RFC2610] is a new protocol, designed from ground up. It uses AES as its cryptographic algorithm, and, since this is more CPU intensive than RC4 (used in WEP and TKIP), new 802.11 hardware may be required. Some drivers can implement CCMP in software. CCMP provides integrity and confidentiality.
3. 802.1X Port-Based Network Access Control: Either when using TKIP or CCMP, 802.1X is used for authentication.
Wireless Access Points
There are two categories of Wireless Access Points (WAPs):
* Autonomous WAPs
* Lightweight WAPs (LWAPs)
Autonomous WAPs operate independently, and each contains its own configuration file and security policy. Autonomous WAPs suffer from scalability issues in enterprise environments, as a large number of independent WAPs can quickly become difficult to manage.
Lightweight WAPs (LWAPs) are centrally controlled using one or more Wireless LAN Controllers (WLCs), providing a more scalable solution than Autonomous WAPs.
Encryption
Encryption is the process of changing data into a form that can be read only by the intended receiver. To decipher the message, the receiver of the encrypted data must have the proper decryption key (password).
TKIP
TKIP stands for Temporal Key Integrity Protocol. It is basically a patch for the weakness found in WEP. The problem with the original WEP is that an attacker could recover your key after observing a relatively small amount of your traffic. TKIP addresses that problem by automatically negotiating a new key every few minutes — effectively never giving an attacker enough data to break a key. Both WEP and WPA-TKIP use the RC4 stream cipher.
TKIP Session Key
* Different for every pair
* Different for every station
* Generated for each session
* Derived from a “seed” called the passphrase