Hide and password-protect any ABAP's source - still runs, but can not be displayed, edited, transported or traced

PROGRAM ZHIDE NO STANDARD PAGE HEADING.
************************************************************************
* This program hides any ABAP's source code and protects it with a
* password. One can still run the abap (the load version is intact)
* but it can not be displayed, edited, traced, transported or generated.
* If the ABAP is not hidden, the program hides it, if it is hidden, it
* unhides it.
* The password is hard-coded in a source code, so the first candidate
* to be hided sholuld be ZHIDE itself.
************************************************************************
SELECTION-SCREEN BEGIN OF BLOCK BLOCK.
SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN COMMENT 1(8) PWD.
SELECTION-SCREEN POSITION 35.
PARAMETERS: PASSWORD(8) MODIF ID AAA.
SELECTION-SCREEN END OF LINE.
PARAMETERS: PROGRAM(8).
SELECTION-SCREEN END OF BLOCK BLOCK.
*
AT SELECTION-SCREEN OUTPUT.
LOOP AT SCREEN.
IF SCREEN-GROUP1 = 'AAA'.
SCREEN-INVISIBLE = '1'.
MODIFY SCREEN.
ENDIF.
ENDLOOP.
*
INITIALIZATION.
PWD = 'PASSWORD'.
*
START-OF-SELECTION.
TABLES: TRDIR.
* User name and passsword check
IF SY-UNAME <> 'IMRE' OR PASSWORD <> 'TITOK'.
WRITE: / 'Wrong password'.
EXIT.
ENDIF.
* SAP owned?
IF NOT PROGRAM CP 'Z*' AND NOT PROGRAM CP 'Y*'.
WRITE: / 'Do not hide original SAP programs!'.
EXIT.
ENDIF.
* Exists?
SELECT SINGLE * FROM TRDIR WHERE NAME = PROGRAM.
IF SY-SUBRC <> 0.
WRITE: / 'Program does not exists!'.
EXIT.
ENDIF.
* Does it have a current generated version?
DATA: F1 TYPE D, F3 TYPE D.
DATA: F2 TYPE T, F4 TYPE T.
EXEC SQL.
SELECT UDAT, UTIME, SDAT, STIME INTO :F1, :F2, :F3, :F4 FROM D010LINF
WHERE PROG = :PROGRAM
ENDEXEC.
IF F1 < F3 OR ( F1 = F3 AND F2 < F4 ).
WRITE: / 'The program has no recent generated version!'.
EXIT.
ENDIF.
* Compose a new program name
DATA: NEW_NAME(8), I TYPE I, J TYPE I.
NEW_NAME = PROGRAM.
DO 8 TIMES.
I = SY-INDEX - 1.
NEW_NAME+I(1) = '_'.
* Search for acceptable program name variations
J = 0.
SELECT * FROM TRDIR WHERE NAME LIKE NEW_NAME.
J = J + 1.
ENDSELECT.
IF J = 1.
EXIT.
ENDIF.
NEW_NAME = PROGRAM.
ENDDO.
* Can not generate appropriate program name
IF J > 1.
WRITE: / 'Can not generate appropriate program name'.
EXIT.
ENDIF.
* Check if it is already in d010s (already hidden)
DATA: F5(8).
EXEC SQL.
SELECT PROG INTO :F5 FROM D010S WHERE PROG = :NEW_NAME
ENDEXEC.
IF F5 IS INITIAL.
* There is no such hidden program, hide it
EXEC SQL.
UPDATE D010S SET PROG = :NEW_NAME WHERE PROG = :PROGRAM
ENDEXEC.
ELSE.
* There is already a hidden program there, unhide it
EXEC SQL.
UPDATE D010S SET PROG = :PROGRAM WHERE PROG = :NEW_NAME
ENDEXEC.
ENDIF.