The LU 6.2 architecture defines a number of conversation-level security option sets that include passwords, user identifiers, and profiles in allocation requests. The LU 6.2 architecture also defines a session-level security option set. The architecture requires that session-level LU-LU verification be allowed when conversation-level security option sets are enabled and when the LUs that make up the network are not physically secure (as determined by installation management).

VTAM® supports session-level security and offers pass-through support for conversation-level security. It is the responsibility of the application programs to implement conversation-level security.

Because VTAM's security support is compatible with the architecture's conversation-level security features, application programs can have conversations with LUs that implement the architecture's security options. These conversations can make use of passwords, user identifiers, and profiles in implementing security procedures.