EDIINT Working Group                                     Dale Moberg
Internet draft                                           Dick Brooks
Expires: November 2001                                  Rik Drummond
                                                       David Fischer
                                                         May 1, 2001

                     HTTP Transport for Secure EDI
                     draft-ietf-ediint-as2-09.txt

Status of this Memo

   This document is an Internet-Draft and is in full conformance
   with all provisions of Section 10 of RFC2026.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other
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   Any questions, comments, and reports of defects or ambiguities in
   this specification may be sent to the mailing list for the EDIINT
   working group of the IETF, using the address
   <ietf-ediint@imc.org>. Requests to subscribe to the mailing list
   should be addressed to <ietf-ediint-request@imc.org>.

Abstract

   This document describes how to exchange structured business data
   securely using HTTP transport for EDIFACT, X12, XML or other
   used for business to business data interchange. The data is
   packaged using standard MIME content-types. Authentication and
   privacy are obtained by using CMS (S/MIME) or OpenPGP security
   body parts. Authenticated acknowledgements make use of
   multipart/signed replies to the HTTP POST requests.

   This document extends the procedures and payload packaging options
   of AS1 in the following ways: HTTPS may be used to obtain data,
   privacy both synchronous and asynchronous reply procedures are,
   described multipart/form-data packaging may be used, a generalized
   multipart/report format is added to the MDN format of AS1, replies
   may include a multipart/mixed payload that contains both the
   acknowledgement and an additional EDI payload.

   This document is intended to be read in conjunction with AS1 and
   the referenced RFCs defining the MIME and cryptographic
   packaging that are used to obtain secure, authenticated, and
   acknowledged transport.

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Feedback Instructions:

   If you want to provide feedback on this draft, follow these
   guidelines:

   - Send feedback via e-mail to the ietf-ediint list for discussion,
     with "AS#2" in the Subject field. To enter/follow the
     discussion, you need to subscribe at ietf-ediint@imc.org.

   - Be specific as to what section you are referring to, preferably
     quoting the portion that needs modification, after which you
     state your comments.

   - If you are recommending some text to be replaced with your
     suggested text, again, quote the section to be replaced, and be
     clear on the section in question.

Table of Contents

1.   Introduction
    1.1   Purpose and relation to previous work
    1.2   Overall operation
2.   Stages and Details of HTTP EDI Transmission and Acknowledgment
    2.1   Requesting Receipts
      2.1.1   Requesting MDN-based receipts
      2.1.2   Requesting Generalized receipts
      2.1.3   Summary Remarks on Receipt request options
    2.2   Additional Commonly Used Headers
    2.3   Sending EDI in HTTP POST Requests
    2.4   Using Transport Layer Security
    2.5   Response Status Codes in Replies
    2.6   Receipt Reply
      2.6.1   MDN Receipts and Signed MDN Receipts
      2.6.2   Generalized Receipts and Signed Receipts
    2.7   Additional Reply Content
    2.8   Non-Repudiation of the POST Reply
    2.9   Error Recovery
3.   Other differences between HTTP and SMTP based transport
    3.1   Unused MIME headers and operations
      3.1.1   Content-Transfer-Encoding not used
      3.1.2   Epilogue must be empty
      3.1.3   Lengthy message bodies
    3.2   Differences in MIME or other headers or parameters used
      3.2.1   Content-Length
      3.2.2   Final Recipient and Original Recipient
      3.2.3   Message-Id and Original-Message-Id
      3.2.4   Host header
      3.2.5   Additional AS2 specific HTTP headers

A.   AS2 MIME templates.
B.   Using AS2 Extensions in the GISB Protocol
C.   Samples of AS2 Protocol Data Units
D.   Acknowledgments
E.   References
F.   Security Considerations
G.   Authors' Addresses


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1.  Introduction

1.1  Purpose and relation to previous work

    Early work on Internet EDI focused on specifying MIME content
    types for EDI data [MIMEEDI] The functional requirements
    document , "Requirements for Interoperable Internet EDI,"
    [EDIINT] provides extensive information on EDI security and the
    business and user processes that can benefit from the use of EDI
    security. In addition, MIME structures appropriate for SMTP
    transport of the packaged EDI data are specified in ([AS1]
    "MIME-based Secure EDI") as well as the details needed to
    support signed receipts as acknowledgments. The framework of
    [AS1] shows how to implement the security features--specifically
    data privacy, data integrity/authenticity, non-repudiation of
    origin and non-repudiation of receipt --found to be requirements
    for secure EDI.

    In this document, it is assumed that the reader is familiar
    with the SMTP/MIME transport document, the requirements document,
    and the RFCs applied or referenced in those documents.

    This draft, like the SMTP/MIME transport document, builds on
    previous RFCs and is attempting to "re-invent" as little as
    possible.  The goal here is to specify how previously specified
    MIME messaging structures and operations can be adapted for use
    with HTTP servers and clients to obtain secure, reliable, and
    acknowledged transport for EDI and other business data.

    The applicability statement, [AS1] "MIME-based Secure EDI,"
    explained the basic EDI transaction using the concept of a
    "secure transmission loop" for EDI. This loop involves one
    organization sending a signed and encrypted EDI interchange to
    another organization, requesting a signed receipt, followed by
    the receiving organization sending this signed receipt back to
    the sending organization. The, transmission therefore, involves
    the following stages:

      1. The organization sending business data encrypts the data
         and provides a digital signature, using either PGP/MIME or
         S/MIME. In addition, they request a signed receipt.

      2. The receiving organization decrypts the message and
         verifies the signature, resulting in verified integrity of
         the data and authenticity of the sender.

      3. The receiving organization then sends a signed receipt
         using a signature over the hash of a message disposition
         notification, which contains a hash of the received message.

    The above stages describe the functionality that would
    satisfy all security requirements. Applications are expected
    to be able to provide full functionality, though users may
    agree to exchange data using only a restricted subset of
    functionality. For example, businesses may agree to send signed
    data using TLS, and only request a simple, unsigned receipt.


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    Implementations are expected to be configurable so that they may
    support business community agreements that use subsets
    of the full functionality.

    In this document, the goal is to make use of HTTP instead of SMTP
    as a transport protocol, and make the changes that are needed to
    adapt to protocol packaging differences.

    In either transport case, the body of the message is a MIME
    structure, using MIME headers ("content-type" and other
    "content-X" tags) to convey information about the data
    being transported.

    Also, one primary use of SMTP RFC 822 headers within SMTP based
    transport of secure EDI has been to enable requests for
    acknowledgements and to specify options for signatures over
    acknowledgements (asymmetric encryption and cryptographic
    hash algorithm preferences).

    One way to convey this information within the HTTP transport
    context is to use either HTTP entity-headers or extension-headers
    [11, section 7.1] that have the syntax of SMTP headers. Only the
    "From" header is overloaded by possibly different usages in the
    SMTP and HTTP contexts. The "From" header normally contains
    machine-usable email addresses  as defined in [SMTPMSG]. The
    usage of the "From" header in [HTTP] section 14.22 is to provide
    the email address of an administrative contact for the HTTP
    client. The function of the "From" header in the SMTP context of
    secure EDI transport has been to supply a value used in
    constructing the MDN style receipt. But the MDN receipt has been
    found to be too restrictive for some commercial EDI transport
    scenarios [GISB]. So alternative receipt mechanisms will be
    provided that, among other things, will remove any conflicts
    arising from trying to reuse the SMTP-MDN roles of
    "From" within the context of HTTP reserved usage of "FROM".

    Also, it is currently difficult to make use of HTML [HTML]
    and simple scripting to send HTTP entity-headers as part of the
    HTML FORM tag construct. For HTML-based POST situations [GISB],
    it is useful to specify ways to convey 'metadata' needed for the
    secure transmission loop that do not make use of HTTP headers.
    One way to specify this data is by using the MIME
    multipart/form-data packaging specified in [FORMDATA].

    For SMTP transport, the receipt and signed receipt functions are
    implemented using Message Disposition Notifications [MDN]
    and Multipart/signed Message Disposition Notifications [AS1].
    For HTTP transport, generalization of the Message Disposition
    Notification is useful.

    The MDN is a special kind of multipart/report [REPORT]. For
    MDNS, specialization is achieved by assigning the "report-type"
    parameter in the content-type  header the special value,
    "disposition-notification" and by having the second body part
    (the "machine-readable" body part) have the MIME content-type,
    "message/disposition-notification".


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    To generalize a MDN, all that is needed is to remove the
    restrictions that make the underlying multipart/report into a
    MDN. In other words, the "report-type" parameter [REPORT,
    section 1] is given a new value and the second body part is
    changed to a content-type other than "message/disposition-
    notification". Acknowledgements defined by these changes will be
    referred to as "generalized receipts. Each receipt of this kind
    will have its own specific report-type parameter and its own
    specifications for the syntax and semantics of the automated
    response body part. Implementations are encouraged to be able to
    register new report-type handlers using only configuration
    changes (not recompiling) that specify how to process new report-
    type values.

    Nothing else needs to be changed to construct reply
    acknowledgements that are not restricted by the semantics of
    MDNs. Specifically, a signed reply will still be constructed by
    using a multipart/signed package to wrap up generalized receipts
    with their signatures.

    Finally, within the HTTP transport context, it is useful to make
    use of Transport Layer Security [TLS] to provide privacy.
    Compression can be provided using HTTP content-codings [HTTP],
    sections 3.5, 14.3, 14.12]. (Content codings are not to be
    confused with the MIME concept of content transfer encodings.)

    A variety of other minor differences (for example, absence of
    content-transfer-encoding) are noted below and summarized in the
    concluding section.

1.2 Overall operation

    A HTTP POST operation [HTTP] is used to send appropriately
    packaged EDI, XML, or other business data. The Request-URI
    ([HTTP],section 9.5) identifies a process to unpack and handle
    the message data and to generate a reply for the client that
    contains a message disposition acknowledgement or a multipart/
    report, signed or unsigned, and possibly other turnaround
    transactions. This request/reply transactional interchange
    provides secure, reliable, and authenticated transport for EDI
    or other business data using HTTP; the security protocols and
    structures used also support auditable records of these
    transmissions, acknowledgements, and authentication.

2. Stages and Details of  HTTP EDI Transmission and Acknowledgment

    A data file or stream is first structured into one of the
    message templates described in [AS1], sections 4.2.1 to 4.2.4 or
    4.3.1 to 4.3.4 for PGP/MIME or S/MIME security. In addition
    to the content-types of [MIMEEDI], applications should be
    prepared for handling other content-types used in business to
    business transactions, such as those for XML [MIME-TYPES].
    For convenience, these message templates, adapted for the
    HTTP transport context, are provided in Appendix A.




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    If TLS is to be used, the typical packaging will be that
    described in sections 4.2.2 or 4.3.2; that is, a multipart/signed
    message will be created with no encryption in the message.
    Otherwise, if privacy is desired, message templates 4.2.4 or
    4.3.4 are used. Content transfer encoding is not used and
    a content-length field is to be provided.

    If HTML-based POST is used (using the METHOD=POST attribute
    within the "FORM" tag) [HTML, 17 Forms], then the message payload
    will be packaged in the input-data element of a multipart/form-
    data. The metadata needed for application layer routing,
    identification, requesting a reply and other transaction
    operations can be packaged in message body parts in the
    multipart/form-data. The labels for the metadata values are found
    in the "name" parameter of the Content-Disposition header in each
    form-data part as discussed in [FORMDATA, section 3].

    In general, both HTTP servers and HTTP clients handling the
    message templates of [AS1] should be prepared to process these
    basic EDIINT data formats when they are embedded within MIME
    multiparts. In addition to the enveloping and MIME media type
    options defined in sections 4.2.x and 4.3.x of "MIME-based Secure
    EDI" [AS1], this specification enables the transport of payload
    objects containing other MIME media types. Implementors are to
    follow the appropriate specifications identified under
    "References" in [MIME-TYPES], for the type of object being
    transmitted. For example, to send an XML object, the MIME media
    type of application/xml is used in the Content-type MIME header
    and the specifications  for enveloping the object are contained
    in [XMLTYPES]; for example:

        Content-type: application/xml; charset="utf-8"

    Many of the specifications referenced by [MIME-TYPES] were
    designed for SMTP transports. Implementors are advised to make
    appropriate adjustments for HTTP transport as indicated in
    section 4 of this document.

    Finally, several industry groups currently make use of
    "encapsulated"(or opaque) signatures within encrypted or
    signed objects. Encapsulated signatures should be supported
    in order to accommodate these existing practices. Objects
    containing encapsulated signatures must be prepared according
    to the specifications contained in  section 3.4.2 of [SMIMEV2]
    or, in the case of PGP, according to the specifications contained
    in section 6.2 of "MIME Security with Pretty Good Privacy (PGP)"
    [MIMEPGP] and "OpenPGP Message Format" [RFC2440].

2.1  Requesting Receipts

2.1.1  Requesting MDN-based receipts

     For requesting MDN based receipts, the originator supplies
     metadata using the syntax of extension headers (the [SMTPMSG]
     header syntax) that precede the message body.



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     The header "tags" are as follows:

     A Disposition-Notification-To header is added to indicate
     that a message disposition notification is requested
     in the reply to the POST request. This header is
     specified in [MDN]. It may have values other than email
     addresses, such as a D-U-N-S number, when it is found as a
     name parameter in a form-data body part When this tag is used in
     HTTP extension headers, it follows the MDN usage.

     A Message-ID header is added to support message reconciliation,
     so that an Original-Message-Id value can be returned in the MDN
     body part of the receipt. (The term "Receipts" is here used
     to refer to the signed or unsigned multipart/report content.)

     Both "From" and "To" extension headers SHOULD be supplied. The
     "From" value needs to have an email address as specified in
     [SMTPMSG] and [HTTP]. If other uses of "From" are needed, the
     generalized receipts to be next discussed should be used. There
     the role of "From" is replaced by symbols not having a reserved
     HTTP or SMTP usage.

     Other headers, especially "Subject" and "Date", should be
     supplied; the values of these headers are often mentioned in the
     human-readable section of a MDN to aid in identifying the
     original message.

     A Disposition-Notification-Options header is used to request
     a signed message disposition notification. The parameters
     used to select protocols for signed message disposition
     notification are found in [AS1].

     Disposition-Notification-To is a name that, if present,
     indicates that the MDN style of receipt is to be used.

     Disposition-notification-options identifies characteristics of
     message disposition notification in accordance with [AS1] and
     [MDN].

     A Receipt-delivery-option is a header whose value is a URL
     that indicates how the receipt is to be delivered. This header
     is only used within AS2. The default mode of operation is
     synchronous within HTTP transport, which means that the receipt
     (be it MDN, signed MDN, generalized report receipt, or signed
     report receipt) is returned in the reply body. By using the
     "receipt-delivery-option," an asynchronous reply mode can be
     requested. The values for this option are URLs that indicate the
     destination for the reply, and may use any appropriate protocol
     ("mailto", "http", and "https" will be the more common types)
     for this information. If this header/metadata is absent, then
     the mode of operation is synchronous, which means that the
     receipt is returned in the reply to the current HTTP request.

2.1.2  Requesting Generalized Receipts

     In this section, the ways to request generalized receipts
     are specified. Generalized receipts are multipart/reports

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     with a report-type other than "disposition-notification," and
     a second automated response with a content type other
     than "message/disposition-notification".

     For requesting generalized receipts using the MIME template for
     multipart/reports [REPORTS], the following metadata elements
     will be useful. A specific example of a generalized receipt
     with report-type "GISB-Acknowledgement-Receipt" will be
     presented in appendix B.

     When the term "metadata" is used in the following, the term
     indicates the information may be supplied in one of two ways:

     First, the metadata information may be supplied using the
     syntax of HTTP headers. That is, the symbol name is followed
     by a colon and its value follows; the header is subject to
     processing of structured field bodies [SMTPMSG, section 3.1.4],
     also including parameters.

     Second, the metadata information may be supplied by using the
     syntax of the "name" parameter within the "Content-Disposition"
     header of the multipart/form-data structure, when that MIME
     packaging [FORMDATA] is used. For example,

          --boundaryformdata
          Content-Disposition: form-data; name="Receipt-Report-Type"

          GISB-Acknowledgement-Receipt
          --boundaryformdata

     Within HTML, the symbols used for these
     names correspond to the value of the name attribute within
     the INPUT element, where the "type" attribute has a "text"
     value. [HTML], section 18; for example,

         <FORM action="http://somesite.com/responder" method="post">
           <INPUT type="text" name="Receipt-Report-Type">
           <INPUT type="submit" value="Send"> <INPUT type="reset">
         </FORM>

     To indicate the various options for generalized receipts, the
     basic metadata that the POSTing client needs to convey to the
     replying server are: "Receipt-Disposition-To", and
     "Receipt-report-type", "Receipt-Security-Selection",
     "Receipt-Delivery-Option".

     The presence of the metadata value "Receipt-Disposition-To",
     using the extension header syntax, indicates a request for a
     generalized receipt.

     Because HTTP already has a role for the "From" header, the
     "Receipt-Disposition-To" header is used to avoid conflicts
     with [HTTP], when using the header syntax for metadata.
     (Within a multipart/form-data package, the "From" value
     can be used to identify the sending party without any
     conflict with HTTP headers.) Notice that the value for this
     identifier need not be an email address or a URL. In this way,

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     other systems of identification (such as a DUNS number) may be
     used, if needed. Notice that the information needed for delivery
     of the receipt is found in the receipt-delivery-option element
     described below; delivery information is not generally needed
     if the default mode of operation occurs. In that case, the
     receipt just goes back in the reply to the current HTTP request.

     "Receipt-Report-Type" indicates the desired value of the
     "report-type" parameter in the multipart/report content type of
     a specific version of the generalized receipt. This parameter
     must be supplied when "Receipt-Disposition-To" is used to
     indicate a request for a generalized receipt because this
     indicates what specific type of receipt is desired. An example
     for this value (discussed in appendix A) is
     "GISB-Acknowledgement-Receipt".

     "Receipt-Security-Selection" is a name that indicates the
     protocol and algorithm choices for a digital signature
     over the receipt. Signatures are always in multipart/signed
     packages. The format for protocol and algorithm choices is
     that used in [AS1] and [MDN]; for example,

         Receipt-Security-Selection:
           signed-receipt-protocol=optional,pkcs7-signature;
           signed-receipt-micalg=optional,rsa-sha1

     "Receipt-Delivery-Option" is used to indicate the
     URL for asynchronous delivery of the receipt.
     While the default mode of operation within HTTP
     transport is to return the receipt(be it MDN, signed
     MDN, generalized receipt, or signed generalized receipt)
     in the reply body, asynchronous reply is allowed through
     use of this symbol. The URLs will typically use the
     "MAILTO", "HTTP", and "HTTPS" schemes.  For the HTTP and
     HTTPS schemes, the POST method is to be used.

2.1.3 Summary Remarks on Receipt request options

     Applications are encouraged to support handling all metadata
     values whether they make use of the name parameter syntax
     within a multipart/form-data or whether they use the message
     header syntax used in SMTP or HTTP headers [SMTPMSG]. If
     metadata items are repeated in extension headers and in
     form-data parts, but the values are not the same, the
     extension header values will be selected for use.

     Because the value in Receipt-Disposition-To may have no
     significance for how the receipt is transported, the extension
     header "Receipt-delivery-option" is to be used to provide
     that information.

     The receipt-delivery-option's value should be a URL indicating
     the delivery transport destination for the receipt.

     The Receipt-delivery-option field is used when asynchronous
     delivery is desired. It should not be present if the intention


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     is to deliver the reply synchronously; synchronous delivery of
     the reply is the default mode of delivery.

     For signed generalized receipts, an extension header of
     "Receipt-security-selection" should be added to indicate the
     desired security protocol for the multipart/signed over the
     multipart/report.

     In summary, the receipt request and construction processes now
     have the following options:

      1. Receipt requests are made by conveying metadata
         values using a syntax of either the name parameter in a
         multipart/form-data's Content-Disposition headers or by
         using a syntax of HTTP extension headers.

      2. Both MDN and generalized receipts can be requested using
         either syntax. However, using an extension header syntax
         and requesting a MDN receipt means restricting the "From"
         values to email addresses.

      3. Either type of receipt comes in signed or unsigned versions.

      4. Finally, receipts may be delivered synchronously (delivered
         in the HTTP reply) or asynchronously by using the
         "Receipt-delivery-option" header.

2.2 Additional Commonly Used Headers

    The following set of header data elements are also available for
    use. Organizations wishing to use this specification for the
    secure and reliable transport of business documents are not
    required to utilize all of these headers and are free to use
    whatever subset they deem appropriate for their business needs.

     TO:
     The To name contains an identifier identifying the
     intended recipient of a data exchange and may be
     D&B D-U-N-S number [DUNS] or other agreed upon
     identifier system. Applications should allow users to
     configure these elements in the automated HTTP agents
     processing these values. For example, the body
     part MIME header line looks like the following line:

         Content-Disposition: form-data; name="To"

     FROM:
     The From name contains a textual value identifying the sender
     of a data exchange, such as the a D&B D-U-N-S number [DUNS] as
     in [GISB]. Because "From" has a specified use within [HTTP],
     the From name parameter is not to be considered equivalent
     to the extension header. If an extension header "From" is
     to be used within HTTP, it should conform to the usage, syntax,
     and semantics of [HTTP] section 14.22. The extension header
     counterpart of the sender of a data exchange is the extension
     header version of "Receipt-disposition-to"


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     INPUT-FORMAT:
     The Input-format name identifies the type of data contained
     in a data file.

     AGENT:
     The Agent name parameter indicates the network or agent
     where the data exchange originated.

     APPLICATION:
     The Application name identifies the application used to process
     the data next (after the URI-request process has finished with
     the stream).

     DATETIME:
     The DateTime name provides the date and time the data was
     created and uses the format specified in [SMTPMSG] as updated
     by RFC 1123.

     REFNUM:
     The RefNum is an integer value used to uniquely identify the
     communication exchange and is in a textual format. The RefNum is
     similar to the Message-ID and Content-Id headers of SMTP that
     are used in constructing values in receipts based on  MDNs.

     USERPARAM:
     The UserParam is a user-defined parameter.

     Version:
     Version is a protocol version number [GISB].

     TRANSACTION-SET:
     Transaction-set is an optional data element identifying the
     EDI transaction.

     INPUT-DATA:
     Input-data is the sending side's local file system name
     for the file being sent. The payload is contained as the body
     part of this header element.

     PRIORITY:
     The "Priority" name is used to indicate the processing priority
     of each message relative to other messages sent by a given
     party. The value "1" indicates highest priority and a value
     of "5" indicates the lowest priority.

     EXPIRATION:
     The "Expiration" name is used to indicate the date and time at
     which a message is no longer transportable. No message delivery
     should be attempted beyond the date and time specified in
     this value.  The date/time format must follow the specifications
     contained in section 5 of RFC822.

2.3 Sending EDI in HTTP Client Requests using POST

    For sending EDI, the following protocol elements are typically
    present: a request line ([HTTP], section 5.1), entity headers, a


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    CRLF pair to mark the end of the entity headers, followed by the
    message-body.

    The request line will have the form: "POST Request-URI HTTP/1.1",
    with spaces and followed by a CRLF. The Request-URI is typically
    exchanged out of band, as part of setting up a bilateral
    trading partner agreement. Applications should be prepared
    to deal with an initial reply containing a status indicating a
    need for authentication of the usual types used for authorizing
    access to the Request-URI ([HTTP], section 10.4.2 and elsewhere).

    Automation of this process is not discussed in this document
    but might involve obtaining a session URL from a page requesting
    authentication and possibly other information about proposed
    EDI standard versions and other trading conventions to be used.

    The request line is followed by entity headers specifying content
    length ([HTTP] section 14.14) and content type [HTTP], section
    14.18. The Host request header ([HTTP] sections 9 and 14.23)
    is also included.

    The entity or extension headers used for requesting a MDN
    (unsigned or signed) have previously been mentioned,
    as have those ("To" "From" "Message-Id") that are needed as
    values for MDN fields or for other receipt requests.

    For generalized receipts based on the multipart/report content
    type, the metadata can be the values found in extension headers,
    but can also be placed in body parts of a multipart/form-data
    using "name" parameters in the content-disposition header.

    Finally, the payload is found in any of the message patterns
    of [AS1] sections 4.2.1 to 4.2.4 or 4.3.1 to 4.3.4 for PGP/MIME
    or S/MIME security. These payloads may arrive as the "input-data"
    part of the multipart/form-data or may even be enclosed in some
    other multipart.

2.4 Using Transport Layer Security

    To use Transport Layer Security [TLS], the request-URI should
    indicate the appropriate scheme value, HTTPS. Usually only a
    multipart/signed message body would be sent using TLS, as
    encrypted message bodies would be redundant. Encrypted message
    bodies are not prohibited, however. For asynchronous receipt
    delivery requests, use the "Receipt-delivery-option" header with
    a URL value making use of the HTTPS scheme to obtain security
    privacy.

2.5  Response Status Codes in Replies

    The status line for response to errors in the POST request line
    will be provided by a status line with the following protocol
    elements present ([HTTP], section 6.1): HTTP version (normally,

    The status codes return status concerning HTTP operations. For
    example, the status code 401, together with the WWW-Authenticate
    header, is used to challenge the client to repeat the request

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HTTP Transport for Secure EDI                            May 1, 2001

    with an Authorization header. Other explicit status codes are
    documented in [HTTP], sections 6.1.1 and throughout section 10.
    HTTP/1.1), a status code, reason phrase, and CRLF.

    For errors in the request-URI, 400 ("Bad Request"), 404
    ("Not Found") and similar codes are appropriate status codes.
    These codes and their semantics are specified by [HTTP].
    A careful examination of these codes and their semantics
    should be made before implementing any retry functionality
    that is described below; specifically, retries should not
    be made if the error is not transient or if retries are
    explicitly discouraged (for real authentication failures,
    for example.)

2.6  Receipt Reply

    The details of the response to the POST command vary depending
    upon whether  a receipt has been requested and upon what kind
    of receipt has been requested.

    With no extended header requesting a receipt, and no errors
    accessing the request-URI specified processing, the status
    line in the Response to the POST request should be in the 200
    range. Status codes in the 200 range should also be used when an
    entity is returned (a signed receipt in a multipart/signed
    content type or an unsigned receipt in a multipart/report).
    Even when the disposition of the data was an error condition
    at the authentication, decryption or other higher level, the
    HTTP status code should indicate success at the HTTP level.

    The HTTP server-side application may respond with an unsolicited
    multipart/report as a message body that the HTTP client
    might not have solicited, but this may be discarded by the
    client. Applications should avoid emitting unsolicited receipt
    replies because bandwidth or processing limitations might
    have led administrators to suspend asking for acknowledgements.

    When a Disposition-Notification-To extension header is present
    in the POST request entity headers, then entity headers for
    the MDN should be included. The content type for the MDN receipt
    (multipart/report [REPORT] or multipart/signed [SECURITY])
    should be included in the Response entity headers.

    The basic responsibilities of responding to requests are
    discussed in [AS1] section 5, and in detail within section 5.2.1.

2.6.1  MDN based Receipts and Signed MDN Receipts

    Message Disposition Notifications, when used in the HTTP
    reply context, will closely parallel a SMTP MDN. For
    example, the disposition field is a required element in the
    machine readable second part of a multipart/report for a
    MDN. The final-recipient-field ([MDN] section 3.1) value
    should be derived from the entity headers of the request.

    If the "To" field is missing, for signed messages, the value for
    Original-recipient may be the email address field from the

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    signer's X.509 attribute for email addresses, if that value is
    available. For a MDN, an application must report the Message-ID
    of the request. The human readable part (the first part of the
    multipart/report) should include items such as the subject, date
    and other information when those fields are present in entity
    header fields following the POST request.

    The HTTP reply should normally omit the third optional part
    of the  multipart/report (used to return the original message
    or its headers in the SMTP context).

2.6.2  Generalized Receipts and Signed Receipts

    For generalized receipts, the multipart/report [REPORT]
    or a multipart/signed containing a multipart/report
    as the signed data is the basic MIME packaging. Each
    generalized receipt needs a value for the multipart/report
    parameter, "report-type," a selection of a content-type
    for its second body part, when signed, a hash value over
    a defined portion of the original message and,
    when asynchronously delivered, information allowing the
    identification of the original POSTed message.

    The basic structure of the multipart/report is used so that
    the first part is a "human-readable" message concerning the
    received message. The second part should be for automated process
    utilization. It should at least possess some common Internet
    syntax for expressing names and values, such as the [SMTPMSG]
    header syntax, XML, or  some MIME content type correlated with
    automated processing.

    The MDN requirements, therefore, are removed for this second
    part, but information used in MDNs may be used here. The third
    part of the multipart report is usually omitted in the HTTP
    context, but could include the extension headers, or even the
    entire payload, to provide diagnostic information.

    A multipart/signed over a multipart/report is constructed
    precisely in the same way as a multipart/signed over a MDN [AS1].

    One metadata element should be within the automated part.
    This is the Received-Content-MIC (also allowing
    X-Received-Content-MIC). This value is constructed and formatted
    as described in [AS1] and the syntax should be either RFC822:

          Received-Content-MIC: w7AguNJEmhF/qIjJw6LnnA==,rsa-md5

    or simple XML

          <ReceivedContentMic algid=rsa-md5 encode=base64 >
           w7AguNJEmhF/qIjJw6LnnA==
          </ReceivedContentMic>

          Original-Message-ID: <43141asfioufasd@somewhere.com>

    Otherwise the automated acknowledgement semantics are left open
    to further semantic specification by specific electronic commerce

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    communities, such as in [GISB]. Each specialization of the
    generalized receipt should make use of a specific identifying
    value to be placed in the parameter "report-type,"

    Any original metadata thought useful to include in the automated
    part may be reflected back using "Original-X", as in

            Content-Type: multipart/report;
                         report-type="identifying-value";
                         boundary="=-Trfds88fd99"

    Implementations should attempt to be configurable to allow
    for new report-type values to be added;  communities can then
    agree to the specific extensions they need to support application
    level routing, transaction identification, timestamps, and
    other specialized information about the data they have exchanged.

2.7  Additional Reply Content

    In general, both HTTP servers and HTTP clients should be prepared
    to process the basic EDIINT data formats when they are embedded
    within MIME multiparts. This is true for HTTP request payloads
    as well as HTTP reply payloads.

    So, as previously mentioned, for HTML-based POSTS, any of the
    EDIINT templates described in [AS1], sections 4.2.1 to 4.2.4 or
    4.3.1 to 4.3.4 for PGP/MIME or S/MIME security, may be found as
    parts of a multipart/form-data. [Consult Appendix A for the
    templates adapted for this document.]

    In addition, the response to the POST operation may include other
    MIME wrapped content besides an MDN Receipt, Signed MDN,
    Generalized Receipt or Signed Generalized Receipt. If a receipt
    was requested within the POST data, and additional content is to
    be returned, the receipt multipart/report must be combined with
    the other data using some MIME multipart pattern. Real-time EDI
    processing systems may use MIME multipart content-types to
    include a response EDI message, for example, a Quote in response
    to a Request-For-Quote transaction.

    Also, if requested, the sender may request an asynchronous mode
    for return of receipt. This mode is indicated by including the
    metadata for Receipt-delivery-option as explained above.

2.8  Non-Repudiation of the POST Reply

    If the reply to a POST operation needs a MDN receipt for non-
    repudiation (for example, the reply includes content other than
    a receipt), the top-level headers in the response include
    the same headers required for POST data described above:
    Disposition-Notification-To, Message-ID, From, and To. Other
    headers described above used in a MDN should be included,
    for example, Date and Subject.

    The MDN receipt of the response data is returned using a
    subsequent POST operation. A POST operation used only to transmit
    an MDN MUST NOT include the Disposition-Notification-To receipt

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    request, and only a 200 ("OK") response would be expected.

    An MDN in response to a reply may be combined with a subsequent
    EDI message sent with a POST operation, for example a
    Purchase-Order transaction in response to a Quote. The MIME
    multipart/mixed form is used to combine the MDN with the other
    data, the same as for a POST reply.

2.9  Error Recovery

    If the HTTP client fails to read the HTTP server response data,
    the POST operation with identical content (including Message-ID,
    RefNum, and other header elements) should be repeated, if the
    error condition is transient.

    The Message-ID or RefNum on a POST operation can be reused if and
    only if all of the content (including the original Date) is
    identical.

    Details of the retry process -- including time intervals to
    pause, number of retries to attempt, timeouts for retrying -- are
    implementation dependent.

    Servers should be prepared to receive a POST with a repeated
    Message-ID. The MIME reply body previously sent should be resent,
    including the MDN and other MIME parts.

3.  Other differences to notice in HTTP and SMTP based transport

    For HTTP version 1.1, TCP persistent connections are the default,
    ([HTTP] sections 8.1.2, 8.2, and 19.7.1).

    A number of other differences exist because HTTP does not
    conform to MIME [MIME] as used in SMTP transport. Relevant
    differences are summarized below.

3.1  Unused MIME headers and operations

3.1.1  Content-Transfer-Encoding not used in HTTP transport

    HTTP can handle binary data and so there is no need to use
    the Content transfer encodings of MIME [MIME]. This difference
    is discussed in [HTTP] section 19.4.4.

3.1.2  Epilogue must be empty

    The EBNF for a multipart [MIME] RFC 2046, section 5.1.1 allows
    a multipart to have trailing octets after the close delimiter.
    In [HTTP] section 3.7.2, it is explicitly noted that multiparts
    must have null epilogues.

3.1.3  Lengthy message bodies

    In [AS1], section 5.4.1, options for large file processing are
    discussed for SMTP transport. For HTTP, large files should be
    handled correctly by the TCP layer. However, [HTTP] sections 3.5
    and 3.6 discuss some options for compressing or chunking entities

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    to be transferred. Section 8.1.2.2 discusses a pipelining option
    that is useful for segmenting large amounts of data.

3.2 Differences in MIME or other headers or parameters used

3.2.1  Content-Length

    Because connections are persistent, closing a connection cannot
    be used to indicate the end of an entity. Therefore, [HTTP]
    sections 4.4 and 14.14 indicate the need for a Content-Length
    entity header in a request.

3.2.2  Final and Original Recipient

    The final and original recipient distinction should not
    arise for HTTP transport because SMTP aliases and mailing
    lists should not be used.

3.2.3  Message-Id and Original-Message-Id

    The Message-Id and Original-Message-Id distinction should not
    arise for HTTP transport because SMTP MTA alterations should
    not occur.

3.2.4  Host header

    The host request header field must be included in the
    POST request made when sending business data. This field
    is to allow one server IP address to service multiple
    hostnames, and potentially conserve IP addresses.
    See [HTTP], sections 14.23 and 19.5.1.

3.2.5  Additional AS2 specific HTTP headers

    The receiving system needs to obtain the identity of the sending
    system. This may be company specific, such as DUNS number, or it
    may be simply an identification string agreed upon between the
    trading partners.

       AS2-From: <textual data>

    The AS2-From: header contains a textual value identifying the
    sender of a data exchange. The sender identifier is required.
    This information MUST appear either in the AS2-From: header or
    in the Form-Data; name="from" (see appendix B).

       AS2-To: <textual data>

    The AS2-To: header contains an identifier identifying the
    intended recipient of a data exchange - DUNS number or other
    agreed upon identifier.  This header contains a textual,
    unformatted string.






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Appendices

A.  AS2 MIME templates

Structure of an AS2 MIME message - PGP/MIME

No encryption, no signature (analog of 4.2.1)

   -RFC2068/2045
     -RFC1767/RFC2376 (application/EDIxxxx or /xml)

No encryption, signature (analog of 4.2.2)

   -RFC2068/2045
     -RFC1847 (multipart/signed)
       -RFC1767/RFC2376 (application/EDIxxxx or /xml)
       -RFC2015 (application/pgp-signature)

Encryption, no signature (analog of 4.2.3)

   -RFC2068/2045
     -RFC1847 (multipart/encrypted)
       -RFC2015 (application/pgp-encrypted)
         -"Version: 1"
       -RFC2015 (application/octet-stream)
         -RFC1767/RFC2376 (application/EDIxxxx or /xml)(encrypted)

Encryption, signature (analog of 4.2.4)

   -RFC2068/2045
     -RFC1847 (multipart/encrypted)
       -RFC2015 (application/pgp-encrypted)
         -"Version: 1"
       -RFC2015 (application/octet-stream)
         -RFC1847 (multipart/signed)(encrypted)
           -RFC1767/RFC2376 (application/EDIxxxx or /xml)(encrypted)
           -RFC2015 (application/pgp-signature)(encrypted)



Structure of an AS2 MIME message - S/MIME

No encryption, no signature (analog of 4.3.1)

   -RFC2068/2045
     -RFC1767/RFC2376 (application/EDIxxxx or /xml)

No encryption, signature (analog of 4.3.2)

   -RFC2068/2045
     -RFC1847 (multipart/signed)
       -RFC1767/RFC2376 (application/EDIxxxx or /xml)
       -RFC2633 (application/pkcs7-signature)




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Encryption, no signature (analog of 4.3.3)

   -RFC2068/2045
     -RFC2633 (application/pkcs7-mime)
       -RFC1767/RFC2376 (application/EDIxxxx or /xml)(encrypted)

Encryption, signature (analog of 4.3.4)

   -RFC2068/2045
     -RFC2633 (application/pkcs7-mime)
       -RFC1847 (multipart/signed)(encrypted)
         -RFC1767/RFC2376 (application/EDIxxxx or /xml)(encrypted)
         -RFC2633 (application/pkcs7-signature)(encrypted)


B.AS2 Extensions for the GISB Protocol and Report-type

    GISB AS2 Profile

    The United States based Gas Industry Standards Board (GISB) is a
    consortium of companies and individuals that operate in the Gas
    Industry. The membership is divided into 5 sectors, Producers,
    Pipelines, Services, End Users, Local Distribution Companies,
    representing the various type of organizations within the
    industry. In 1996 GISB initiated a program to move from the
    expensive Value Added Networks they were using, to the Internet.
    By October of 1996GISB had developed and tested a protocol,
    called GISB Electronic Delivery Mechanism (EDM), which uses HTTP
    and is based on RFC1867 (Form-based File Upload in HTML). By
    May 1997 this protocol was being used by Enron and others to
    send/receive live, mission critical business transactions over
    the Internet.  Additional companies followed suit and a large
    percentage of today's business transactions in the Gas Industry
    are transmitted over the Internet using the GISB EDM protocol. In
    1998 the Automobile Industry Action Group (AIAG) adopted the GISB
    EDM protocol and in 1999 the local electric companies serving the
    state of Pennsylvania declared the GISB protocol as their
    standard for transmitting business transactions via the Internet.

    In May of 1999 the AIAG, GISB and members of the IETF EDIINT
    workgroup initiated an effort to converge their independent
    specifications, the result of which is this specification. In
    order to bring the GISB EDM into compliance with this
    specification GISB initiated a formal change to the EDM
    specification. The following information, referred to as the
    "GISB AS2Profile", reflects the planned utilization of this
    specification by the GISB membership.

    The GISB membership will utilize PGP to meet all P.A.I.N.
    requirements. All data exchanges will utilize the multipart/form-
    data enveloping method and two generalized receipts, GISB-
    Acknowledgement-Receipt and GISB-Error-Notification. All original
    business transactions must be digitally signed (using
    encapsulated signatures) and encrypted using RSA algorithms. Upon
    successful transfer of an original business transaction the
    receiver is required to send a GISB-Acknowledgement-Receipt
    indicating that the transfer has completed successfully. If, upon

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HTTP Transport for Secure EDI                            May 1, 2001

    further processing of the business document an error is
    encountered a GISB-Error-Notification is sent to the original
    sender using the multipart/form-data enveloping.

    It is expected that companies following the GISB AS2 profile will
    protect their web sites from unauthorized access through the use
    of basic authentication (username/passwords), as defined in the
    HTTP specification. GISB is not "requiring" the use of signed
    receipts; however, signed receipts are allowed between consenting
    trading partners. GISB has decided to use the following core
    headers:

        FROM:
        Contains the DUNS number of the sending party

        TO:
        Contains the DUNS number of the intended recipient

        INPUT-FORMAT:
        Type of data being sent (only x12 and error currently
        supported) other options can easily be added to this list.

        INPUT-DATA:
        The actual payload containing the business transaction or
        GISB-Error-Notification.  If the payload contains a business
        transaction it is signed and encrypted using PGP.

        Version:
        The GISB version number (currently 1.3)

        RECEIPT-DISPOSITION-TO:
        The DUNS number of the party to receive the
        GISB-Acknowledgement-Receipt (typically the same DUNS
        number associated with the From header.) Presence of this
        field also serves as a flag indicating that an
        acknowledgement receipt is requested by the sender. The
        receipt is returned synchronously (on the same session
        used to send the input-data payload).

        RECEIPT-REPORT-TYPE:
        Contains the value GISB-Acknowledgement-Receipt.

    Optional headers also available:

        TRANSACTION-SET:
        Identifies the type of transaction contained in the
        input-data payload.

        RECEIPT-SECURITY-SELECTION:
        This field serves as a flag indicating that a signed
        receipt is being requested. The contents of this field
        indicate the algorithm and signature type to use in
        constructing the signature.

    Example of a GISB data exchange:

        The sending party creates an X12 business transaction and

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HTTP Transport for Secure EDI                            May 1, 2001

        concatenates with an RFC 1767 compliant header. The entire
        package is then encrypted and signed using PGP. The encrypted
        package is then enveloped with the appropriate headers/values
        and sent to the trading partner using HTTP POST, the contents
        of this post appear as follows:

    POST c:\execute HTTP/1.0
    Referer: http://www.get.a.life/upl.htm
    Connection: Keep-Alive
    User-Agent: brow v0.1 XYZ Corp.
    Host: localhost
    Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*
    Content-type: multipart/form-data;
       boundary=---------------------------87453838942833
    Content-Length: 5379

    -----------------------------87453838942833
    Content-Disposition: form-data; name="from"

    123456789
    -----------------------------87453838942833
    Content-Disposition: form-data; name="to"

    234567890
    -----------------------------87453838942833
    Content-Disposition: form-data; name="Version"

    1.3
    -----------------------------87453838942833
    Content-Disposition: form-data; name="receipt-disposition-to"

    123456789
    -----------------------------87453838942833
    Content-Disposition: form-data; name="receipt-report-type"

    GISB-Acknowledgement-Receipt
    -----------------------------87453838942833
    Content-Disposition: form-data; name="input-format"

    x12
    -----------------------------87453838942833
    Content-Disposition: form-data; name="input-data";
      filename=c:\temp\smallnom.bin
    Content-Type: multipart/encrypted; boundary=8760;
      protocol="application/pgp-encrypted"

    --8760
    Content-Type: application/pgp-encrypted

    Version: 1

    --8760
    Content-Type: application/octet-stream

    -----BEGIN PGP MESSAGE-----
    Version: PGP 6.5


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HTTP Transport for Secure EDI                            May 1, 2001

    hQCMAzRG1pEOIOvdAQP+JMr0m/9+8yOL60Z9Vr6fFV81FCExB/o0xmwiMkiwYsHs
    z0e8sb7ErC340MrNA/dw3taGMjmI+CXYRF/PLEdg1NZE1ZCtNeL4YdIHAMLWwODG
    lQxhSucz8rMSgQ5mZzcOJwBdWLW70efgsu/9UljuJjYc1uZ6C03eFQv/43fkB+al
    ATtgydxX4g8QK664ad+Jo/XUICSmWBL66fqJR1KLeLf4wTaqGy174Aq48Wpwvg1E
    h785zC03UAw0qg0ugMt86dPeyd91e2JigqwDYEf/DYEKD0J9BGiGpS/uAupNKj8O
    aqx2Dq/ra9g65HNchOCzjul5Vi8HHf6Yhg2WnROe+npByyCue6rihqgNVOJwj0cV
    zpb4JE+gMDf3q4ISUb1Fv7/+SSFHDdnhdC5YTpqf1Bc3B07hiLmtTXqNit31EbX9
    UVElObzSa9ZhxbC6/eSl7Nuf5ZTDsh9nrk+QQJ6FeC9W4cqXLj7IZySaRO8Vtff+
    4ktqeuhYusT4kSpnk027aw4O/5jomUkfb22CAe4=
    =Oiuo
    -----END PGP MESSAGE-----

    --8760--

    -----------------------------87453838942833--

        Upon receiving the above stream of data the receiving host
        parses the headers and returns an unsigned
        GISB-Acknowledgement-Receipt, appearing as follows:

    Content-Type: multipart/report;
      report-type="GISB-Acknowledgement-Receipt"; boundary="GISB7867"

    --GISB7867
    Content-type: text/html

    <HTML><HEAD><TITLE>Acknowledgement Receipt Success</TITLE></HEAD>
    <BODY><P>
    time-c=19960619082855*
    request-status=ok*
    server-id=coolhost*
    trans-id=234423897*
    </P> </BODY></HTML>

    --GISB7867
    Content-type: text/plain

    time-c=19960619082855*
    request-status=ok*
    server-id=coolhost*
    trans-id=234423897*

    --GISB7867--

C.  Samples of AS2 Protocol Data Units

C.1 The following example illustrates the full HTTP request that
    sends X12 EDI data from company1 to company2. A signed receipt is
    requested; the receipt is to be a MDN report-type, with the pkcs7
    signature option, using a signature algorithm of rsa-md5.

    The receipt is to be sent synchronously (that is, in the reply to
    this HTTP request), because no special delivery options are
    indicated.

POST https://tp2server.company2.com/cgi-bin/tp1drawer.pl HTTP/1.1
Host: tp2server.company2.com

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AS2-To: zzzcompany2
AS2-From: zzzcompany1
From: ediadmin@company1.com
Date: Tue, 06 Nov 2001 12:53:01 UT
Subject: Purchase orders for 6 November 2001
Message-Id: <20011106@company1.com>
Disposition-Notification-To: tp1@company1.com
Disposition-Notification-Options: signed-receipt-protocol=optional,
    pkcs7-signature; signed-receipt-micalg=optional,rsa-md5
Content-Type: multipart/signed; boundary="20011106RsXgYlvCNW";
    protocol=application/pkcs7-signature; micalg=rsa-md5
Content-Length: 3056

--20011106RsXgYlvCNW
Content-Type: application/edi-x12
Content-Disposition: Attachment; filename=rfc1767.dat

  [ISA ...EDI transaction data...IEA...]
--20011106RsXgYlvCNW
Content-Type: application/pkcs7-signature

  [omitted binary pkcs7 signature data]
--20011106RsXgYlvCNW--

C.2 This second example illustrates returning a signed MDN
    that corresponds to the request for a MDN found in C.1.

        HTTP/1.0 200 OK
        Server: HTTPEDI/1.1
        Content-type: multipart/signed; boundary="boundary1"
        Content-Length: 1200

        --boundary1
        Content-type: multipart/report; boundary="boundary2"

        --boundary2
        Content-type: text/plain

        Message <20011106@company1.com> was authenticated;
        EDI processing was initiated.

        --boundary2
        Content-type: message/disposition-notification

        Reporting-UA: Company2UA
        Final-Recipient: rfc822; tp2@company2.com
        Original-Message-Id: <20011106@company1.com>
        Received-Content-MIC: w7AguNJEmhF/qIjJw6LnnA==, rsa-md5
        Disposition: MDN-sent-automatically/processed

        --boundary2--

        --boundary1
        Content-Type: application/pkcs7-signature

           [Signature data omitted]
        --boundary1--

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D. Acknowledgments

   Carl Hage, Karen Rosenfeld, Chuck Fenton and many others have
   provided valuable suggestions improving this applicability
   statement.

E. References

 [AS1]  T. Harding, R. Drummond, "MIME-based Secure EDI", Internet
     draft: draft-ietf-ediint-as1-12.txt.

 [CMS]  R. Housley, "Cryptographic Message Syntax", RFC 2630,
     June 1999.

 [FORMDATA]  L. Masinter, "Returning Values from Forms:
     multipart/form-data", RFC 2388, August, 1998.

 [GISB]  Gas Industry Standards Board, "Electronic Delivery
       Mechanism Related Standards", Version 1.3 July 31, 1998

 [HTML]  D. Raggett, A. Le Hors, I. Jacobs.  "HTML 4.0
     Specification", World Wide Web Consortium Technical Report
     "REC-html40", December, 1997. <http://www.w3.org/TR/REC-html40/>

 [HTTP]  R. Fielding, J.Gettys, J. Mogul, H. Frystyk, T. Berners-Lee,
     "Hypertext Transfer Protocol--HTTP/1.1", RFC 2068, January 1997.

 [MIME]  N. Borenstein, N.Freed, "Multipurpose Internet Mail
     Extensions (MIME) Part One: Format of Internet Message Bodies",
     RFC 2045, December 02, 1996.

     N. Borenstein, N.Freed, "Multipurpose Internet Mail Extensions
     (MIME) Part Two: Media Types", RFC 2046, December 02, 1996.

     N. Borenstein, N.Freed, "Multipurpose Internet Mail Extensions
     (MIME) Part Five: Conformance Criteria and Examples", RFC 2049,
     December 02, 1996.

 [MIMEEDI]  D. Crocker, "MIME Encapsulation of EDI Objects", RFC
     1767, March 2, 1995.

 [MIMEPGP]  M. Elkins, "MIME Security With Pretty Good Privacy
     (PGP)", RFC 2015, Sept. 1996.

 [MDN]  R. Fajman, "An Extensible Message Format for Message
     Disposition Notifications", RFC 2298, March 1998.

 [SECURITY]  J. Galvin, S. Murphy, S. Crocker, N. Freed, "Security
     Multiparts for MIME: Multipart/Signed and Multipart/Encrypted",
     RFC 1847, Oct. 3, 1995

 [SMTP]  J. Postel, "Simple Mail Transfer Protocol", STD 10, RFC 821,
     August 1, 1982.

 [SMIMEV2]  S. Dusse, P. Hoffman, B. Ramsdell, L. Lundblade, L.
     Repka, "S/MIME Version 2 Message Specification", RFC 2311.


Moberg, Brooks, Drummond                                   [page 24]


HTTP Transport for Secure EDI                            May 1, 2001

 [SMIMEV3]  B. Ramsdell, "S/MIME Version 3 Message Specification",
     RFC 2633, June 1999.

 [SMTPMSG]  D. Crocker, "Standard for the Format of ARPA Internet
     Text Messages", STD 11, RFC 822, August 13, 1982.
     (Also RFC 1123 provides important updates on date and time
     formats as well as email addresses.)

 [REPORT]  G. Vaudreuil, "The Multipart/Report Content Type for the
     Reporting of Mail System Administrative Messages", RFC 1892,
     January 15, 1996.

 [TLS]  T. Dierks,C. Allen, "The TLS Protocol Version 1.0" RFC 2246,
     January 1999.

 [MIME-TYPES]  "Media Types," http://www.isi.edu/in-
       notes/iana/assignments/media-types/media-types.

 [EDIINT]  T. Harding, R. Drummond, "Requirements for Interoperable
       Internet EDI", Internet draft: draft-ietf-ediint-req-09.txt.

 [XMLTYPES]  E. Whitehead, M. Murata, "XML Media Types", RFC 2376,
     July 1998.

F. Security Considerations

    This entire document is concerned with secure transport of
    business to business data, and considers both privacy and
    authentication issues.

G.  Authors' Addresses

    Dale Moberg
    dale_moberg@stercomm.com
    Sterling Commerce
    4600 Lakehurst Ct.
    Dublin, OH 43016 USA

    Dick Brooks
    dick@8760.com
    Group 8760
    110 12th Street North
    Suite F103
    Birmingham, Alabama 35203
    Tel: 205-250-8053

    Rik Drummond
    rik@drummondgroup.com
    Drummond Group
    5008 Bentwood Ct.
    Fort Worth, TX  76132 USA

    David Fischer
    david@drummondgroup.com
    Drummond Group
    4200 S. Hulen St.  Suite 600
    Fort Worth, TX  76109 USA

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