ABSTRACT
Although a number of studies on data security have been published in the last
decade, many security breaches still occur because some newly introduced
security protocols exhibit the vulnerabilities arising from the already known
security problems. For example, the initial version of the IEEE 802.11 wired
equivalent privacy (WEP) protocol allowed broadcasting of access point iden-
tifiers as cleartext so that a man-in-the-middle attack with a fake identifier was
easily possible. Or, the encryption key length used in the WEP by default did
not fulfill the requirements of the current standards for strong cryptography,
that is, they used a 64-bit key instead of a 128-bit key. Therefore, it is of crucial
importance to study and understand the fundamental security principles
explained in this chapter.
