PROC main:
rem Juergen Galupki http://galupki.de ;-)

Global PassW$(80), Secret$(80)

PRINT "zu verschluesselnder Text"
INPUT Secret$
PRINT "Passwort"
INPUT PassW$

Encrypt:(Secret$, PassW$)

PRINT Secret$
GET

Encrypt:(Secret$, PassW$)

PRINT "Ergebnis"
PRINT Secret$

PROC Encrypt (Secret$, PassW$)
REM secret$ = the string you wish to encrypt or decrypt.
REM PassWord$ = the password with which to encrypt the string.
      L = LEN(PassW$)
      FOR x = 1 TO LEN(Secret$)
         Char = ASC(MID$(PassW$, (x MOD L) - L * ((x MOD L) = 0), 1))
         MID$(Secret$, x, 1) = CHR$(iXor:(ASC(MID$(Secret$, x, 1)), Char))
      NEXT
ENDP

PROC iXor:(a, b)
  RETURN (NOT a AND b) + (a AND NOT b)
ENDP