What is MIC (Message Integrity Check)?

MIC (Message Integrity Check) is part of a draft standard from IEEE 802.11i working group.

The MIC (Message Integrity Check) is an additional 8 byte field which is placed between the data portion of an 802.11 (Wi-Fi) frame and the 4 byte ICV (Integrity Check Value).

The MIC has a function very similar to the older ICV. However, the ICV only protects the packet payload. The MIC protects both the payload and the header.

The algorithm which implements the MIC is known as Michael. Michael also implements a frame counter, which discourages replay attacks.

Some analysts refer to MIC as a component of TKIP.