SCRAMBLE is a command used to encode a CP/M file.

The format of the command is:
	SCRAMBLE filename.type password
where "password" is an 8 character password made of characters
perissible in a file name (i.e. no ".", etc).  To obtain a good
"initial seed" for the scrambling process, no character in the
password may appear more than twice.

The requested file is scrambled, and re-written in place.
To un-scramble the file, the IDENTICAL command is issued,
i.e. SCRAMBLE filename.type password.  This is because
SCRAMBLE does an "exclusive-or" type modification to the file,
and doing two identical exclusive-or's to data result
in the same data being retuned. 

I feel a scrambled file is quite secure.  Given that a file
was scrambled and the password forgotten, I know of no way to
determine what the original file was.  Even a file which
is all binary-0's, is sufficiently scrambled to defy finding
out what the password or original data was.  ...But I assume
no responsibility for the "security" of files scrambled
with SCRAMBLE as I am not a "student of cryptology".

Note also, that if an attempt is made to unscramble a scrambled
file, using the WRONG password, then the file is technically
"double scrambled" and SCRAMBLE would then have to be executed
TWICE, once with the original password, and once with the
erroniously-used password.  Because of the exclusive or-ing
process, either password may be used either time.

03/11/79 Ward Christensen