## Presentation Device Driver Reference for OS/2

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### Secure Level

Secure DCAF offers a higher and more advanced level of security for environments such as banks and insurance companies that work with confidential material. You can make a target workstation almost impregnable to intruders by designating it as a secure target. The controller must access the secure target through a secure gateway.

A secure session exists between a controlling workstation and a gateway or target workstation that has been installed as a secure gateway or target. These secure workstations do not have passwords. Instead, the controller, authorized to access a secure gateway or target, has a personal pass phrase (a compound password) and an access-level profile for a specific secure workstation.

DCAF security works with the following communication connections only:

A controller can connect to a secure gateway via APPC/APPN or asynchronous .

The secure Gateway can connect to a secure target via NetBIOS only.

The Example of a DCAF Environment with Session Security figure shows some workstations in a secure DCAF environment. The gateway can use only NetBIOS to communicate with the secure targets. Secure targets must be on a LAN ( see targets C and D in the following figure.) [Artwork not shown]

Controller A communicates via secure gateway B with the secure targets on the LAN. When the controller wants to take over secure target C, security authenticator D verifies that the controller is authorized to access that workstation.

DOS or Windows target E on the LAN is not secure and does not require authentication. It has password-only security. Controller A can also establish a session with secure target workstation F. Typically, the secure DCAF gateway, LAN directory, and security authenticator reside on target workstation F. In this case, controller A connects to gateway F via APPC, and gateway F connects internally to target F via NetBIOS.

The security administrator is typically installed on a controller workstation. It provides security file maintenance, a message log file, and control access information used by the DCAF security authenticators, all in a central location. Security files are transferred from the security administrator via a secure session to all of the remote security authenticators. Security administrator workstation G transfers new or updated security files to security authenticators D and F.

When the controller wants to change a pass phrase, the security authenticator verifies the authorization before a session is allowed, and keeps a log file of the authentication activity. The verification compares the controller's input with the ciphered data stored on the security authenticator. The advantage of this mechanism is that there is no way to intercept or discover the pass phrase during transmission, because only the ciphered data is sent.

For auditing purposes, the gateway logs all session connections and the communication errors that it filters.