ABSTRACT
The true test of a first-rate mind is the ability to hold two contradictory ideas at the same time.
F. Scott Fitzgerald (1896-1940), American Novelist
Issues of authentication were discussed at various points previous to this chapter, such as the presentation of Kerberos in Section 5.2 page 195; in Section 5.7, page 220, in the presentation of SSL and issues surrounding it; in Section 6.1, page 233, when we described authentication issues surrounding key management; and in Section 6.3, page 243, when we delved into the details of SET. We also looked at attacks on authenticity, such as the impersonation attack presented on page 180, and methods for thwarting it. This impersonation attack is essentially a man-in-the-middle attack, which we introduced in Footnote 3.7, page 134. This was in reference to authentication issues in the use of the various modes of operation about which we learned in Section 3.3. Thus, we are fairly well versed in authentication issues to date. Now we want to look at authentication functions, such as MACs, which we briefly mentioned on page 136.
