IEEE 802.11i is an IEEE 802.11 amendment used to facilitate secure end-to-end communication for wireless local area networks (WLAN). IEEE 80211i improves mechanisms for wireless authentication, encryption, key management and detailed security.
IEEE 802.11i is also known as IEEE 802.11i-2004.
Techopedia explains IEEE 802.11i
IEEE 802.11i enhances Wired Equivalent Policy (WEP), which was a defacto wireless security standard until it was replaced by the draft version of Wi-Fi Protected Access (WPA). When combined, IEEE 802.11i and WPA 2 form a complete wireless security protocol that includes the Advanced Encryption Standard's (AES) block ciphering technique, four-way handshake and group key handshake for improved authentication and access control.
IEEE 802.11i also incorporates Temporal Key Integrity Protocol (TKIP) and Counter Mode/CBC-MAC Protocol (CCMP) for data transmission confidentiality, protection, packet authentication and encryption.