Simple Introduction to WPA encryption

After finding the flaws of WEP, Wi-Fi Protected Access (WPA) was invented to replace it and provide higher security level.
Compared with WEP, WPA has doubled the length of IV and the Temporal Key Integrity Protocol (TKIP) could dynamically generates new key for each packet and the check algorithm has been upgraded. the "Michael" has replaced the CRC (Cyclic Redundancy Check). The following Figures show the configuration of two level of WPA keys:

1. Pairwise Key

2. Group Key