
Chapter 6 • The IP Security Protocol (IPsec) 93
protocols, and exchange any keys or other material or information
necessary to provide security services.
As may be evident from its highly qualified description, public key
cryptography-based mechanisms require that all participants can be con-
fident that public keys are issued only to the entities identified with those
keys. When a public key is published purporting to represent Microsoft
Corporation, the possibility that the key has been properly issued to
Microsoft and not to a computer criminal should approach 100% certainty.
Unfortunately, as was demonstrated in early 2001 when it was reported
that