In networking, IEEE 802.11i is a security standard designed to enhance the security of wireless local area networks (WLANs) defined by the 802.11 standards.
Understanding IEEE 802.11i
IEEE 802.11i was developed to address the security vulnerabilities present in the original 802.11 standard, particularly those found in Wired Equivalent Privacy (WEP). It forms the basis for what is commonly known as WPA2.
According to the IEEE reference, IEEE 802.11i enhances IEEE 802.11-1999 by providing a Robust Security Network (RSN) with two new protocols: the four-way handshake and the group key handshake.
This means that 802.11i defines how wireless devices can securely connect to a network, ensuring data privacy and integrity. It introduced a stronger framework than its predecessors.
Key Components Introduced by 802.11i
The core enhancements brought by 802.11i, as highlighted by the reference, revolve around the concept of a Robust Security Network (RSN) and key management protocols.
- Robust Security Network (RSN): This is a network that allows only the creation of Robust Security Network Associations (RSNAs). Essentially, it's a WLAN operating in a mode that guarantees strong security.
- New Key Management Protocols: 802.11i introduced sophisticated mechanisms for managing encryption keys:
- The Four-Way Handshake: This protocol is used to establish a secure connection between a client device (supplicant) and an access point (authenticator) after they have been mutually authenticated (often via 802.1X). It's crucial for deriving and distributing the Pairwise Transient Key (PTK), which is used to encrypt the data traffic between the client and the access point.
- The Group Key Handshake: This protocol is used to securely update the Group Transient Key (GTK). The GTK is used to encrypt multicast and broadcast traffic sent from the access point to multiple clients.
These protocols utilize the authentication services and port access control described in IEEE 802.1X to establish and change the appropriate cryptographic keys. This highlights the integration of 802.11i with the 802.1X standard for enterprise-level authentication, although 802.11i also supports a pre-shared key mode (like WPA2-PSK) suitable for home use.
Comparison with Previous Standards
To understand the significance of 802.11i, it's helpful to see how it improved upon earlier standards:
| Feature | WEP (Pre-802.11i) | WPA (Interim) | WPA2 (Based on 802.11i) |
|---|---|---|---|
| Standard | Original 802.11 | Wi-Fi Alliance (TKIP) | IEEE 802.11i (AES-CCMP) |
| Encryption | RC4 with weak key management | TKIP (Temporal Key Integrity Protocol) | AES-CCMP (Advanced Encryption Standard with Counter Mode with Cipher Block Chaining Message Authentication Code Protocol) |
| Key Mgmt. | Simple, vulnerable | Improved (TKIP algorithms) | Robust Security Network (RSN) with Four-Way & Group Key Handshakes |
| Authentication | Shared Key, Open System | 802.1X or PSK | 802.1X or PSK, integrated with key management |
WPA was a temporary solution using TKIP to address WEP vulnerabilities before the full 802.11i standard was finalized and implemented as WPA2.
Practical Implication
In practice, when you secure your Wi-Fi network with WPA2, you are utilizing the security protocols defined by IEEE 802.11i. This standard provides a much stronger level of protection against unauthorized access and data eavesdropping compared to older methods like WEP. It is the recommended security protocol for modern Wi-Fi networks.
