In this chapter we have seen that there are many ways in which attacks can be mounted against security systems. Methods do not need to be sophisticated to be effective, nor does the person making the attack need to be a technical expert if he is using a tool written by such an expert. Most security attacks in the past have come from bad passwords or dictionary attacks. However, key derivation is helping to reduce this problem. Now attackers must look for flaws in the algorithms?or at least weaknesses that allow the strength of the keys to be compromised.

The special vulnerability of Wi-Fi LANs makes them susceptible to all these attacks and means that the security protections chosen must be extremely good. By the end of this book, you will see how the new Wi-Fi and IEEE 802.11 security methods are, indeed, that good.

    Part II: The Design of Wi-Fi Security