INT 21 - DR DOS 5.0-6.0 internal - GET ENCRYPTED PASSWORD

	AX = 4304h
	DS:DX -> ASCIZ filename
	???
Return: CF clear if successful
	    CX = AX = 0000h if no password assigned to file
	CF set on error
	    AX = error code (see #01680 at AH=59h/BX=0000h)
Note:	this function is only supported by DR DOS 5.0 and 6.0 and DRMDOS 5.1
SeeAlso: AX=4303h,AX=4305h