HP-UX System Administrator's Guide: Security Management HP-UX 11i v3 (B3921-90020, September 2010)

third-party
attack
In a third-party attack, the attacker intercepts packets between two attacked parties, A and B. A
and B assume they are exchanging messages with each other, but are exchanging messages with
the third party. The attacker assumes the identity of A to exchange messages with B, and assumes
the identity of A to exchange messages with B. Also referred to as man-in-the-middle attack.
transitive trust
relationship
Extending a trust relationship through other trusted entities. If A and B both trust C, A and B can
trust each other using a transitive trust relationship through C. In a hierarchical structure, A and
B can establish a transitive trust relationship if they can establish a chain-of-trust to a common
root.
VPN Virtual Private Network. A private network within a public network, such as the global Internet.
A VPN is virtual because it uses tunnels to effectively create a separate logical network within a
physical network. A VPN is private because outside users cannot see or modify the data being
transmitted. VPNs that use host identity authentication also provide protection against IP address
spoofing.
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