CONCEAL


Michael J. Mefford                          September 26, 1990 (Utilities)

Purpose:	Provides file security through password protection of 
selected files and a screen-blanking system activated either by a hotkey or 
by a period of keyboard inactivity.  Most options explained below have ON and 
OFF states (default on) that may be entered with the parameters.

Format:	CONCEAL [/P password] [filespec] [options]

Remarks:	CONCEAL.COM is normally loaded as a TSR requiring 
approximately 1K of RAM, via the AUTOEXEC.BAT line 

	CONCEAL /S

	Files are then protected with the command

	CONCEAL filespec /S

	This applies the DOS System attribute to the filespec, making it 
invisible to DOS.  CONCEAL then monitors and fails any attempts to remove the 
System attribute, and any DOS calls to open, delete, rename, or change the 
file attribute of protected files unless the proper password is supplied.  
Legitimate access is provided by the command

	CONCEAL /P password filespec /S OFF

	This turns off the filespec System attribute, which must later be 
reapplied.  (The /F option allows password-access without removing the System 
attribute, but may not work with all applications.)  The default password 
SHAZAM can be changed with the /N parameter option.  Other file attributes 
(Archive, System, Hidden, Read-only) can be changed with the /A option: 

	CONCEAL /A filespec [+|-A] [+|-S] [+|-H] [+|-R]

	Hardware screen blanking is provided by entering 

	CONCEAL /B nn

	where nn is a number of minutes (0 - 60).  The default is 3 minutes, 
and a value of 0 for nn turns blanking off.  The /G option may be entered 
instead of /B to provide a bouncing ball instead of a blank screen display.  
Instant blanking is achieved with a hotkey (default Alt-Z), which may be 
changed to any Alt- or Ctrl- alphanumeric key with the /H option.  From 
graphics mode, the /G option defaults to /B.  To blank over graphics 
applications such as Windows, use the /O parameter.  Adding the /T switch 
will require password entry rather than a simple keystroke to terminate 
screen blanking. The /U switch uninstalls CONCEAL.