Wi-Fi Protected Access (WPA), Wi-Fi Protected Access II (WPA2), and Wi-Fi Protected Access 3 (WPA3) are the three security and security certification programs developed by the Wi-Fi Alliance to secure wireless computer networks. The Alliance defined these in response to serious weaknesses researchers had found within the previous system, Wired Equivalent Privacy (WEP). WPA (sometimes mentioned because the draft IEEE 802.11i standard) became available in 2003. The Wi-Fi Alliance intended it as an intermediate measure in anticipation of the supply of the safer and sophisticated WPA2, which became available in 2004 and may be a common shorthand for the complete IEEE 802.11i (or IEEE 802.11i-2004) standard. In January 2018, Wi-Fi Alliance announced the discharge of WPA3 with several security improvements over WPA2. The Wi-Fi Alliance intended WPA as an intermediate measure to require the place of WEP pending the supply of the complete IEEE 802.11i standard. WPA might be implemented through firmware upgrades on wireless network interface cards designed for WEP that began shipping as far back as 1999. However, since the changes required within the wireless access points (APs) were more extensive than those needed on the network cards, most pre-2003 APs couldn't be upgraded to support WPA. The WPA protocol implements much of the IEEE 802.11i standard. Specifically, the Temporal Key Integrity Protocol (TKIP) was adopted for WPA. WEP used a 64-bit or 128-bit encryption key that has got to be manually entered on wireless access points and devices and doesn't change. TKIP employs a per-packet key, meaning that it dynamically generates a replacement 128-bit key for every packet and thus prevents the kinds of attacks that compromised WEP. WPA also includes a Message Integrity Check, which is meant to stop an attacker from altering and resending data packets. This replaces the cyclic redundancy check (CRC) that was employed by the WEP standard. CRC's main flaw was that it didn't provide a sufficiently strong data integrity guarantee for the packets it handled. Well-tested message authentication codes existed to unravel these problems, but they required an excessive amount of computation to be used on old network cards. WPA uses a message integrity check algorithm called TKIP to verify the integrity of the packets. TKIP is far stronger than a CRC, but not as strong because the algorithm utilized in WPA2. Researchers have since discovered a flaw in WPA that relied on older weaknesses in WEP and therefore the limitations of the message integrity code hash function, named Michael, to retrieve the keystream from short packets to use for re-injection and spoofing.