arbitrary binary data.  The set of currently defined parameters is:

    (1)   TYPE -- the general type or category of binary data.
          This is intended as information for the human recipient
          rather than for any automatic processing.

    (2)   PADDING -- the number of bits of padding that were
          appended to the bit-stream comprising the actual
          contents to produce the enclosed 8bit byte-oriented
          data.  This is useful for enclosing a bit-stream in a
          body when the total number of bits is not a multiple of
          8.

   Both of these parameters are optional.

   An additional parameter, "CONVERSIONS", was defined in RFC 1341 but
   has since been removed.  RFC 1341 also defined the use of a "NAME"
   parameter which gave a suggested file name to be used if the data
   were to be written to a file.  This has been deprecated in
   anticipation of a separate Content-Disposition header field, to be
   defined in a subsequent RFC.

   The recommended action for an implementation that receives an
   "application/octet-stream" entity is to simply offer to put the data
   in a file, with any Content-Transfer-Encoding undone, or perhaps to
   use it as input to a user-specified process.




 
RFC 2046                      Media Types                  November 1996


   To reduce the danger of transmitting rogue programs, it is strongly
   recommended that implementations NOT implement a path-search
   mechanism whereby an arbitrary program named in the Content-Type
   parameter (e.g., an "interpreter=" parameter) is found and executed
   using the message body as input.

4.5.2.  PostScript Subtype

   A media type of "application/postscript" indicates a PostScript
   program.  Currently two variants of the PostScript language are
   allowed; the original level 1 variant is described in [POSTSCRIPT]
   and the more recent level 2 variant is described in [POSTSCRIPT2].

   PostScript is a registered trademark of Adobe Systems, Inc.  Use of
   the MIME media type "application/postscript" implies recognition of
   that trademark and all the rights it entails.

   The PostScript language definition provides facilities for internal
   labelling of the specific language features a given program uses.
   This labelling, called the PostScript document structuring
   conventions, or DSC, is very general and provides substantially more
   information than just the language level.  The use of document
   structuring conventions, while not required, is strongly recommended
   as an aid to interoperability.  Documents which lack proper
   structuring conventions cannot be tested to see whether or not they
   will work in a given environment.  As such, some systems may assume
   the worst and refuse to process unstructured documents.

   The execution of general-purpose PostScript interpreters entails
   serious security risks, and implementors are discouraged from simply
   sending PostScript bodies to "off- the-shelf" interpreters.  While it
   is usually safe to send PostScript to a printer, where the potential
   for harm is greatly constrained by typical printer environments,
   implementors should consider all of the following before they add
   interactive display of PostScript bodies to their MIME readers.

   The remainder of this section outlines some, though probably not all,
   of the possible problems with the transport of PostScript entities.

    (1)   Dangerous operations in the PostScript language
          include, but may not be limited to, the PostScript
          operators "deletefile", "renamefile", "filenameforall",
          and "file".  "File" is only dangerous when applied to
          something other than standard input or output.
          Implementations may also define additional nonstandard
          file operators; these may also pose a threat to
          security. "Filenameforall", the wildcard file search
          operator, may appear at first glance to be harmless.




 
RFC 2046                      Media Types                  November 1996


          Note, however, that this operator has the potential to
          reveal information about what files the recipient has
          access to, and this information may itself be
          sensitive.  Message senders should avoid the use of
          potentially dangerous file operators, since these
          operators are quite likely to be unavailable in secure
          PostScript implementations.  Message receiving and
          displaying software should either completely disable
          all potentially dangerous file operators or take
          special care not to delegate any special authority to