Hamming distance as a metric for the detection of side channel in 802.11 wireless communications
A wireless network can be exploited in many ways. One way is through intentionally corrupting the Frame Check Sequence (FCS) field by using a different Cyclic Redundancy Check (CRC) polynomial in order to create a side channel. Malicious nodes exploit the fact that normal unsuspecting nodes will immediately drop erroneous frames. A metric called the Hamming Distance (HD) was proposed for detection which distinguishes legitimate from illegitimate errors. The idea is to apply this HD measure to compare CRC values that are generated by different CRC polynomials. The hypothesis is that the average HD between two CRC values generated by two different CRC polynomial would be significantly far apart than those that are generated by the same CRC polynomial. The results show that this HD metric is effective in detection of side channel frames.