/CONFIRM
       /NOCONFIRM
    Controls whether or not a confirmation request is displayed
    before each decryption, as follows:
    Response         Meaning
    YES              Decrypts the file
    NO or <Return>   Does not decrypt the file (default)
    QUIT or          Does not decrypt the file or any subsequent
    <Ctrl/Z>         files
    ALL              Decrypts the file plus all subsequent files