MIC

Message Integrity Check (or Code), also called ‘Michael‘, is part of WPA and TKIP (Temporal Key Integrity Protocol). The MIC is an additional 8-byte code inserted before the standard 4-byte ICV (Integrity Check Value) appended in by standard WEP (Wired Equivalent Privacy) to the 802.11 message. This greatly increases the difficulty in carrying out forgery attacks. 
Both integrity check mechanisms are calculated by the receiver and compared against the values sent by the sender in the frame. If the values match, there is assurance that the message has not been tampered with.