ΜΟΓΛ®ΓΟΝ¬ ΥΞΜΟΓΛ®ΓΟΝ αξδ ΝΛΕΩ®ΓΟΝ


The programs LOCK, UNLOCK and MKEY are for the protection of
those very private files you might leave in a shared system, or
that other people might get a chance to copy off one of your
disks.

Give

	LOCK (filename or filematch) (keyword)

to lock one or more (up to 32) files.  The keyword can be up to
eight characters (no distinction between lower case and
capitals).  Once a file is locked, any attempt to read it with
TYPE, or ED, or a word processor, or to execute it as a .COM
file, will just give the message

	==<Locked file>==

And if your local spooks get out a debugger such as DDT, or
whatever, to look into the file itself, they'll find that the
contents have been fairly thoroughly scrambled.

To reverse the process, give

	UNLOCK (filename or match) (keyword)

- with, of course, the same keyword.

The MKEY program is in case you forget your keyword; you give

	MKEY (filename)

and it tells you what it was.  Naturally, this means you
shouldn't leave copies of MKEY lying around for spooks to use. 
If copies of MKEY are to be public at all, they should be
"locked" (with an unforgettable keyword!). 
You are not protected from people assiduous enough to
disassemble the programs and break the code.  But they'll have
a bit of work to do.


Γυστονισιξη ωους γοπιεσ®  Near the end of each of the three
listings is a table of "mush" - random bytes used in the coding
process.  You can customise your copies by altering this table.
 It will usually be sufficient to alter the eight bytes at the
address "nmush", which are used in coding the keyword.	But
alter all of it if you wish.  Make the same alterations in all
three programs.


Ν―ΠΝ βυζζσΊ  The lock-unlock system is more flexible in use
(and more secure) than M/PM password facilities.  Note that,
for your benefit, LOCK alters a .PRL extension to .LRL, and
UNLOCK alters it back.