Internet Info 1994 March/Internet Info CD-ROM (Walnut Creek) (March 1994).iso/inet/internet-drafts/draft-vaudreuil-mime-sig-00.txt

Text File | 1993-10-18 | 11.4 KB | 372 lines

     Network Working Group                             Gregory M. Vaudreuil
     Internet Draft                                       Tigon Corporation
     Expires 4/18/94                                     October 18th, 1993



                             Application/Signature
                       <draft-vaudreuil-mime-sig-00.txt>


     1.Status of this Memo


     This document is an Internet Draft.  Internet Drafts are working
     documents of the Internet Engineering Task Force (IETF), its Areas,
     and its Working Groups.  Note that other groups may also distribute
     working documents as Internet Drafts.

     Internet Drafts are valid for a maximum of six months and may be
     updated, replaced, or obsoleted by other documents at any time.  It is
     inappropriate to use Internet Drafts as reference material or to cite
     them other than as a "work in progress".


     2.Abstract

     The memo defines a MIME content type for the exchange of sender
     contact information and user agent capability information beyond what
     is feasable in the RFC822 header.  This exchange is generally
     accomplished by use of a signature trailer appended to the message.
     These signatures commonly contain address, phone, and email
     addressing.  This document outlines a formalization and extension of
     the signature concept to provide a machine readable, internationally
     friendly form to exchange this information.

     3.Introduction

     Mechanisms for the exchange of contact information are lacking in the
     general internet.  Directory services are not ubiquitous and it is not
     clear how to search for a given person even when they are available.
     The exchange of business cards provides a mechanism for identifying a
     specific person when you meet them.  The application/signature body
     part provides a similar mechanism, to deliver contact information to a
     person you "meet" over electronic mail.

     The information to be exchanged between people over electronic mail is
     also growing.  As Privacy Enhanced Mail grows in popularity, accessory
     information such as public keys becomes more essential to exchange
     with those who you normally contact.  As Internet mail becomes multi-
     media, the exchange of information, such as a small portrait or short
     audio greeting become as useful as the RFC822 text name for
     identifying the sender.

     As the number of content-types, languages, and character sets
     increase, it becomes more essential to identify the capabilities of
     the destination mail agents without having to wait for error reports
     and letters of complaint.  The Application/Signature body part


     Internet Draft     Application/Signature     Expires 4/10/93


     provides a mechanism for sending a list of MIME content-types, the
     character sets supported, and the languages spoken by the mailbox
     owner.

     By saving and caching the information provided in the
     application/signature body part, a database of destinations frequently
     contacted can be populated and updated.  This database can be used for
     providing basic, local alias directory services and can be used by
     mailers to notify the sender before sending the message if it is
     supported by the receiver.

     Automated update of the database requires loosely standardized
     attribute/value pair definitions.  These elements are based on the
     MIME content-type/sub-type registry.  Each attribute registration
     includes all information needed to unambiguously identify the content-
     type, parameters such as character set, and transport encoding.

     This specification does not explicitly include a universal database
     key value.  X.500 distinguished names and email addresses may provide
     a suitable mechanism for correlating updates and providing lookup
     functions.

     4.Definition of the Application/Signature Body Part


     Mime type name: Application
     Mime Sub-Type name: Signature
     Required Parameters: None
     Optional Parameters: None
     Encoding Considerations: 7 bit is always sufficient.

     The application/signature body part should be included as the last
     body part in a top-level Multipart/Mixed construct.

     The Application/Signature body part is a sequence of attribute/value
     pairs formatted according to the rules of RFC 822 header lines.  As in
     RFC822 headers, lines may be wrapped and continued on subsequent lines
     by indenting with linear white space.  Comments are optional and are
     not considered part of the value if included.

     All lines must be in 7bit US ASCII format.  Non US ASCII textual data
     can be represented using the RFC 1522 encoded word.  Non-text data
     must be encoded using base-64 or quoted printable, with the specific
     encoding specified in the attribute definition.

     The list of allowable attributes is maintained by the IANA.  Except
     for Text/Plain, registered values must correspond to exactly one
     previously registered MIME content-subtype and must include constant
     values for all necessary parameters and specify the transport encoding
     if needed.  Use of X- for experimental and bi-laterally defined
     (Private) values is permitted.

     The attribute "Capabilities" is provided to identify the MIME content-
     types supported by the destination.  The list of attributes should


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     include any IANA registered content-type.  To reduce the amount of
     data transferred, the list of capabilities should not include the
     basic MIME constructor types.  These types are Message/RFC822,
     Message/Partial, Multipart/Mixed, Multipart/Parallel,
     Multipart/Alternative, and Application/Octet-Stream.  Text/Plain if
     supported should be explicitly identified as some mixed media agents
     may not support text output.

     The attribute "Charsets" is provided to identify the character sets
     accepted for use in Text/* bodyparts.  The list of character sets can
     include any IANA registered character set. US-ASCII does not need to
     be identified as it the default character set.  The character sets
     should be listed in the order of preference.

     The attribute "Languages" is provided to communicate the languages
     understood by the mailbox owner.  As communication becomes increasing
     global, a list of languages will allow the sender to choose an
     appropriate language without guessing.  The set of language identifier
     can include any registered in XXXXX(need reference). The languages
     should be listed in the order of preference.




































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       Initially Defined Application/Signature Values      .     5



     Attribute     Content Type    Description
                   Encoding


     Email         Text/Plain      A fully qualified domain name style
                   7bit            address.


     Name          Text/Plain      The name of the mailbox owner. Latin
                   7bit            derived names must be in the Last, First,
                                   Middle initial format for ease of parsing.


     Telephone     Text/Plain      The international version of the telephone
                   7bit            number. Multiple telephone numbers can be
                                   differentiated by use of an RFC 822
                                   comment.


     Fax           Text/Plain      The international verison of the
                   7bit            fascimilie number.


     Address       Text/Plain      The postal address, each line separated
                   7bit            with a slash "/".


     Portrait      Image/Gif       A small bitmap portrait. This may be used
                   Base-64         for visual message waiting identification.


     SpokenName    Audio/ADPCM     A short phrase containing the name in the
                   Base-64         voice of the mailbox owner.


     Capabilities  Text/Plain      A coma separated list of the MIME content-
                   7bit            types the mailbox owner is willing to
                                   accept. Message/RFC822, Message/Partial,
                                   Multipart/Mixed, Multipart/Parallel, and
                                   Multipart/Alternative are required and
                                   need not be listed.



     Text          Text/Plain      Free form text for comments, quotes, and
                   7bit            ASCII art.






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     Charsets      Text/Plain      A coma separated prioritized list of the
                                   MIME content-types supported by the user
                                   agent.


     Languages     Text/Plain      A coma separated prioritized list of the
                                   languages understood by the mailbox owner.


     PEM_Cert      Text/Plain      The PEM certificate of the mailbox owner
                   7bit            as specified in RFC 1421.


     Distname      Text/Plain      The X.500 distinguished name of the
                   7bit            mailbox owner.








































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     6.Example Application/Signature Body Part

     Content-Type: Application/Signature

     Name:       Gregory M. Vaudreuil
     Email:      [e-mail]
     Telephone:  [phone] (Work)
     Fax:        [phone]
     Address:    17080 Dallas Parkway/Suite 100/Dallas Texas, 75248
     Portrait:   R0lGODdhEAAQAIAAAAAAAP///ywAAAAAEAAQAAACK4wNqceR7UCT8FB
                 n2aUc47550nZ5iFZWVqpG2bS+WhbK3frYrYmwOaRYMAoAOw==
     Capabilities: Text/Plain, Image/GIF, Image/Postscript, Audio/Basic
     PEM-Cert:
         MIIBlTCCAScCAWUwDQYJKoZIhvcNAQECBQAwUTELMAkGA1UEBhMCVVMxIDAeBgNV
         BAoTF1JTQSBEYXRhIFNlY3VyaXR5LCBJbmMuMQ8wDQYDVQQLEwZCZXRhIDExDzAN
         BgNVBAsTBk5PVEFSWTAeFw05MTA5MDQxODM4MTdaFw05MzA5MDMxODM4MTZaMEUx
         CzAJBgNVBAYTAlVTMSAwHgYDVQQKExdSU0EgRGF0YSBTZWN1cml0eSwgSW5jLjEU
         MBIGA1UEAxMLVGVzdCBVc2VyIDEwWTAKBgRVCAEBAgICAANLADBIAkEAwHZHl7i+
         yJcqDtjJCowzTdBJrdAiLAnSC+CnnjOJELyuQiBgkGrgIh3j8/x0fM+YrsyF1u3F
         LZPVtzlndhYFJQIDAQABMA0GCSqGSIb3DQEBAgUAA1kACKr0PqphJYw1j+YPtcIq
         iWlFPuN5jJ79Khfg7ASFxskYkEMjRNZV/HZDZQEhtVaU7Jxfzs2wfX5byMp2X3U/
         5XUXGx7qusDgHQGs7Jk9W8CW1fuSWUgN4w==

     7.Security Consideration

     The information in the application/signature cannot be considered any
     more authoritative than the "from" line of the RFC 822 header.
     Authentication of the content is left to mechanisms specified in the
     Privacy Enhanced Mail extension to RFC 822.


     8.Author's Address

     Gregory M. Vaudreuil
     The Tigon Corporation
     17080 Dallas Parkway
     Dallas, TX 75248-1905
     214-733-2722
     [e-mail]

















     Vaudreuil                                           [Page 6]