$CPU 8086          ' make compatible with XT systems
$LIB ALL OFF       ' turn off all PowerBASIC libraries
$ERROR ALL OFF     ' turn off all PowerBASIC error checking
$OPTIMIZE SPEED    ' optimize for smaller code
 $COMPILE UNIT      ' compile to a UNIT (.PBU)
'$COMPILE EXE       ' compile to a UNIT (.PBU)

DEFINT A-Z         ' Required for all numeric functions, forces PB to not
                   ' include floating point in UNIT (makes it smaller)
'/*------------------------------------------------------------------*/
$CODE SEG "MLIB5"
'/*------------------------------------------------------------------*/
'   FUNCTION ENCRYPTZ(BYVAL PTC$, BYVAL PW$) AS STRING
'     x1 = 1
'     FOR x2 = 1 TO LEN(PTC$)
'       c1 = ASC(MID$(PTC$, x2, 1))
'       c2 = ASC(MID$(PW$, x1, 1))
'       c3 = c1 XOR c2
'       Encrypted$ = Encrypted$ + CHR$(c3)
'       INCR x1
'       IF x1 > LEN(PW$) THEN
'         x1 = 1
'       END IF
'     NEXT x2
'     FUNCTION = Encrypted$
'   END FUNCTION
'/*------------------------------------------------------------------*/
    FUNCTION ENCRYPTER(BYVAL S$, PW$, N%) AS STRING
      PW$ = PW$ + "+_)(*&^%$#@!:{}?><,./;'[]=-0987654321"
      V$ = ""
      FOR CNT = 32 TO 255
        V$ = V$ + CHR$(CNT)
      NEXT CNT
      VL = LEN(V$)
      LS = LEN(S$)
      J8 = 0
      FOR I8 = 1 TO LS
        J8 = J8 + 1
        IF J8 > LEN(PW$) THEN J8 = 1
        S8 = INSTR(1,V$,MID$(S$,I8,1))
        IF N = 1 THEN
          S8 = S8 + INSTR(1,V$,MID$(PW$,J8,1))+10
          IF S8 > VL THEN
            S8 = S8 - VL
          ELSE
            GOTO ENCRYPT2JUMP
          END IF
        ELSE
            S8 = S8 - INSTR(1,V$,MID$(PW$,J8,1))-10
            IF S8 <= 0 THEN S8 = S8 + VL
        END IF
        ENCRYPT2JUMP:
        MID$(S$,I8,1) = MID$(V$,S8,1)
      NEXT I8
      FUNCTION = S$
    END FUNCTION
'/*------------------------------------------------------------------*/
' ENCRYPT(STRING$,PASSWORD$)
'     Returns a string where the STRING$ has been encrypted using the phrase
'     in PASSWORD$.
'     EXAMPLE: T$ = ENCRYPT("THE MOON","PASSWORD")    T$ = '�tƒ^�‰Œ}'
'
'     See DECRYPT
'/*------------------------------------------------------------------*/
    FUNCTION ENCRYPT(S$,PW$) PUBLIC AS STRING
      FUNCTION = ENCRYPTER(S$,PW$,1)
    END FUNCTION
'/*------------------------------------------------------------------*/
' DECRYPT(STRING$,PASSWORD$)
'     Returns a string where the STRING$ has been decrypted using the phrase
'     in PASSWORD$.
'     EXAMPLE: T$ = DECRYPT("�tƒ^�‰Œ}","PASSWORD")    T$ = '�tƒ^�‰Œ}'
'
'     See ENCRYPT
'/*------------------------------------------------------------------*/
    FUNCTION DECRYPT(S$,PW$) PUBLIC AS STRING
      FUNCTION = ENCRYPTER(S$,PW$,0)
    END FUNCTION
'/*------------------------------------------------------------------*/
'   $INCLUDE "C:\CODE\MLIB\MLIB.INC"
'   LINE INPUT "PHRASE "; PTC$
'   INPUT "Password";  PW$
'
'   ENCRYPTED$ = ENCRYPT(PTC$, PW$)
'   DECRYPTED$ = DECRYPT(ENCRYPTED$, PW$)
'
'   PRINT "   PHRASE: "; CHR$(34); PTC$      ; CHR$(34)
'   PRINT "ENCRYPTED: "; CHR$(34); ENCRYPTED$; CHR$(34)
'   PRINT "DECRYPTED: "; CHR$(34); DECRYPTED$; CHR$(34)
'
'   Y$ = GETKEY