User's Manual Part 4

FILE AUTHENTICATION
Introduction to File Authentication
106 OMNI 3600 REFERENCE MANUAL
Determine Successful Authentication
To ensure the Omni 3600 terminal’s logical security, never assume that a target
file was authenticated simply because it downloaded to the Omni 3600 terminal
together with its signature file.
There are several ways to ensure a target file successfully authenticated after a
download:
• Confirm all downloaded executable files run. If an executable code file is
not successfully authenticated, the operating system does not allow it to
execute and run, either following the initial download or on subsequent
terminal restarts. The effect of this rule depends on whether or not all
executable files successfully authenticated:
• If the executable file that failed to authenticate is the main application
(*.out) specified in the CONFIG.SYS *GO variable, the main application is
not allowed to run.
• If the executable that failed to authenticate is a secondary executable
(*.out) or shared library (*.lib) used by the main application, the
CONFIG.SYS *GO application executes and runs until it issues a function
call to that library. When the main application attempts to access a non-
authenticated executable, the main application may crash.
• Visually (and audibly) confirm file authentication during the process.
When the file authentication module is invoked at terminal restart and detects
a new signature file, it displays status information on screen indicating
success or failure of the authentication of each target file based on its
corresponding signature file. (A similar status display also appears on screen
when you download digital certificates.)
You can watch the screen display following the download to see if a specific
target file fails to be authenticated. If this happens,
FAILED displays on screen
for five seconds below the filenames of the target and signature files, and the
terminal beeps as an alert.
An application program can issue a function call to read the
ATTR_NOT_AUTH bit’s current value for all relevant files to verify that were
successfully authenticated. If the ATTR_NOT_AUTH bit’s binary value is 1,
the file did not authenticate; if 0, the file did authenticate.
For non-executable files, it is the application’s responsibility to confirm that all
of the files it uses successfully authenticated on download completion, and
when the application executes the first time following a restart.
NOTE
Because the application is responsible for verifying data files and prompt files, it is
recommended that each application check the ATTR_NOT_AUTH bit of all
relevant files on restart.