EDIINT Working Group Terry Harding
Internet draft Richard Scott
Expires: September 2004
March 2004
FTP Transport for Secure Peer-to-Peer
Business Data Interchange over the Internet
draft-ietf-ediint-as3-02.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 working documents of the Internet Engineering
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Copyright Notice
Copyright (c) The Internet Society (2002). All rights reserved.
Abstract
This Applicability Statement (AS) describes how to exchange structured
business data securely using the File Transfer Protocol (FTP) for XML,
Binary, Electronic Data Interchange (EDI - ANSI X12 or UN/EDIFACT), or
other data used for business-to-business data interchange for which
MIME packaging can be accomplished using standard MIME content-types.
Authentication and data confidentiality are obtained by using
Cryptographic Message Syntax (S/MIME) security body parts.
Authenticated acknowledgements employ multipart/signed replies to the
original message.
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Feedback Instructions:
NOTE TO RFC EDITOR: This section should be removed
by the RFC editor prior to publication.
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#3" in the Subject field. To enter or follow the discussion,
you need to subscribe to 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
2. Overview
2.1 Overall operations
2.2 Purpose of a security guideline for MIME EDI
2.3 Definitions
2.4 Operational assumptions and options
2.4.1 EDI process assumptions
2.4.2 Process options
2.4.2.1 Security options
2.4.2.2 Compression options
3. Referenced RFCs
3.1 RFC 959 File Transfer Protocol
3.2 RFC 2228 FTP Security Extensions
3.3 RFC 1847 MIME Security Multiparts
3.4 RFC 1892 Multipart/report
3.5 RFC 1767 EDI Content
3.6 RFC 2045, 2046, 2049: MIME
3.7 RFC 2298 Message Disposition Notification
3.8 RFC 2633, 2630: S/MIME Version 3 Message Specifications
3.9 RFC 2632 S/MIME Version 3 Certificate Handling
3.10 RFC 3274 Compressed Data Content for Cryptographic Message Syntax
3.11 RFC 3023 XML Media Types
4. Structure of an AS3 message
4.1 Introduction
4.2 Structure of EDI MIME message
5. AS3-specific headers
5.1 AS3-From and AS3-To headers
5.2 AS3-Version header
6. FTP Considerations
6.1 FTP Security Requirements
6.2 Large File Transfers
6.3 MIME Considerations for FTP
6.3.1 Required/Optional Headers
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6.3.2 Content-Transfer-Encoding Not Used
6.3.3 Epilogue Must be Empty
6.3 Modification of MIME or other headers or parameters used
6.3.1 Required/Optional Headers
6.3.2 Content-Transfer-Encoding Not Used
6.3.3 Epilogue Must Be Empty
6.3.4 Message-Id and Original-Message-Id
7. Structure and Processing of an MDN Message
7.1 Introduction
7.2 Message Disposition Notifications (MDN)
7.3 Requesting a signed receipt
7.3.1 Signed receipt considerations
7.4 MDN Format
7.4.1 AS3-MDN General Formats
7.4.2 AS3-MDN Construction
7.4.3 AS3-MDN Fields
7.4.4 Additional AS3-MDN Programming Notes
7.5 Disposition Mode, Type, and Modifier
7.5.1 Disposition Mode Overview
7.5.2 Successful Processing Status Indications
7.5.3 Unsuccessful Processed Content
7.5.4 Unsuccessful Non-Content Processing
7.5.5 Processing Warnings
7.5.6 Backwards Compatibility with Disposition Type, Modifier, and
Extension
7.6 Receipt Reply Considerations in a FTP Post
8. Public key certificate handling
9. Security Considerations
10. Acknowledgements
11. References
12. Authors' Addresses
Appendix
A. Message Examples
B. IANA Registration Form
1. Introduction
Previous work on Internet EDI focused on specifying MIME content types
for EDI data [2] and extending this work to support secure EC/EDI
transport over SMTP [5]. This document expands on RFC 1767 to specify
a comprehensive set of data security features, specifically data
privacy, data integrity, authenticity, non-repudiation of origin and
non-repudiation of receipt over FTP. This document also recognizes
contemporary RFCs and is attempting to "re-invent" as little as
possible. While this document focuses on EDI data, any other data type
describable in a MIME format are also supported.
Internet MIME based EDI can be accomplished by using and complying
with the following RFC's and Internet drafts:
-RFC 959 File Transfer Protocol
-RFC 2228 FTP Security Extensions
-RFC 1767 EDI Content Type
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-RFC 3023 XML Media Types
-RFC 1847 Security Multiparts for MIME
-RFC 1892 Multipart/Report
-RFC 2045 to 2049 MIME RFC's
-RFC 2298 Message Disposition Notification
-RFC 2630, 2632, 2633: S/MIME v3 Specifications
-RFC 3274 Compressed Data Content for Cryptographic Message Syntax
-draft-ietf-ediint-compression-02.txt
Our intent here is to define clearly and precisely how these are used
together, and what is required by user agents to be compliant with this
document.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
2.0 Overview
2.1 Overall Operations
A FTP upload operation is used to send appropriately-packaged EDI,
XML, or other business data. The receiving application will poll
the FTP server for inbound messages, unpackage and handle the message
data and generate a reply for the originator that contains a
message disposition acknowledgement within a multipart/report that is
signed or unsigned. This request/reply transactional interchange
provides secure, reliable, and authenticated transport for EDI or
other business data using FTP. The security protocols and structures
used also support auditable records of these transmissions.
2.2 Purpose of a security guideline for MIME EDI
The purpose of these specifications is to ensure interoperability
between B2B Electronic Commerce user agents, invoking some or all of
the commonly expected security features. This document is also NOT
limited to strict EDI use, but applies to any electronic commerce
application where business data needs to be exchanged over the
Internet in a secure manner.
2.3 Definitions
2.3.1. Terms
EDI Electronic Data Interchange
EC Business to Business Electronic Commerce
B2B Business to Business
Receipt The functional message that is sent from a
receiver to a sender to acknowledge receipt of
an EDI/EC interchange.
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Signed Receipt A receipt containing a digital signature.
Message Disposition The Internet messaging format used to convey a
Notification (MDN) receipt. This term is used interchangeably with
receipt. A MDN is a receipt.
Non-repudiation of NRR is a "legal event" that occurs when the
receipt (NRR) original sender of an EDI/EC interchange has
verified the signed receipt coming back from the
receiver. NRR IS NOT a functional or a technical
message.
S/MIME A format and protocol for adding Cryptographic
signature and/or encryption services to Internet
MIME messages.
NOTE: While the S/MIME specification describes
more than one format for a signed message,
all signed messages or receipts used with
AS3 MUST utilize the multipart/signed format.
SHA-1 A secure, one-way hash algorithm used in
conjunction with digital signature. SHA-1 is the
recommend algorithm for AS3.
MD5 A secure, one-way hash algorithm used in
conjunction with digital signature. This
algorithm is acceptable but not recommended
due to its short key length and known weaknesses.
MIC The message integrity check (MIC) is a representation
of the message digest, which results from the
application of the selected hash algorithm to the
content to be signed. Of particular interest is the
the digital signature, which includes an encrypted
copy of the digest. Additionally, an MDN containing
a "Received-Content-MIC" header will also contain
(as that header's value) a base-64 encoded
representation of the digest.
User Agent (UA) The application that handles and processes the
AS3 request.
STL Secure Transmission Loop, described in the next
section
2.3.2 The Secure Transmission Loop
This document's focus is on the formats and protocols for exchanging
EDI/EC content to which security services have been applied using
the File Transmission Protocol (FTP) as the transport.
The "Secure Transmission Loop" (STL) comprises the following two steps:
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a) The originator sends a signed and encrypted document with a
request for a signed receipt.
b) The recipient decrypts the document, verifies the signature,
and returns a signed receipt to the sender.
In other words, the following events occur during the execution of the
STL:
- The organization sending EDI/EC data signs and encrypts the data
using S/MIME. In addition, the message will request a signed
receipt to be returned to the sender of the message.
- The receiving organization decrypts the message and verifies the
signature, resulting in verified integrity of the data and
authenticity of the sender.
- The receiving organization then returns a signed receipt, as
requested to the sending organization in the form of a message
disposition notification. This signed receipt will contain the
hash of the signature from the received message, indicating to
the sender that the received message was verified and/or decrypted
properly.
The above describes functionality which, if implemented, will
satisfy all security requirements and provide non-repudiation of
receipt for the exchange. While trading partners will usually want
to utilize the STL, this specification does not require it.
2.3.3 Definition of Receipts
The term used for both the functional activity and the message for
acknowledging delivery of an EDI/EC interchange is "receipt" or
"signed receipt". The term receipt is used if the acknowledgment
is for an interchange resulting in a receipt which is NOT signed.
The term signed receipt is used if the acknowledgment is for an
interchange resulting in a receipt which IS signed. A term often
used in combination with receipts is non-repudiation of receipt.
NRR refers to a legal event which occurs only when the original
sender of an interchange has verified the signed receipt coming back
from the recipient of the message. Note that NRR is not possible
without signatures.
For additional information on formatting and processing receipts
in AS3, refer to section 7.
2.4 Operational assumptions and options
2.4.1 EDI/EC process assumptions
- Encrypted object is an EDI/EC Interchange
This specification assumes that a typical EDI/EC interchange is the
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lowest level object that will be subject to the application of
security services.
Specifically, for EDI ANSI X12, the entire document (including
the ISA and IEA segments) is the atom to which security is applied.
For EDIFACT, the corresponding definition includes segments UNA/UNB
and UNZ. In other words, EDI/EC interchanges including envelope
segments remain intact and unreadable during secure transport.
- EDI envelope headers are encrypted
Congruent with the above statement, EDI envelope headers are
NOT visible in the MIME package. In order to optimize routing
from existing commercial EDI networks (called Value Added Networks
or VANs) to the Internet, work may need to be done in the future to
define ways to extract some elements of the envelope to make
them visible; however, that is beyond the scope of this specification.
- X12.58 and UN/EDIFACT security considerations
The most common EDI standards bodies, ANSI X12 and EDIFACT, have
defined internal provisions for security. X12.58 is the security
mechanism for ANSI X12 and AUTACK provides security for EDIFACT.
This specification DOES NOT dictate use or non-use of these security
standards. They are both fully compatible, though possibly
redundant, with this specification.
2.4.2 Process options
2.4.2.1 Security options
- Encrypted or un-encrypted data
This specification allows for EDI/EC message exchange where the
EDI/EC data can be either un-protected or protected by means of
encryption.
- Signed or unsigned data
This specification allows for EDI/EC message exchange with or
without digital signature of the original EDI transmission.
- Use of receipt or not
This specification allows for EDI/EC message transmission with or
without a request for receipt notification. If a signed receipt
notification is requested however, a MIC value is REQUIRED as
part of the returned receipt, unless an error condition occurs which
results in the inability to compute a valid digest. (Such a case would
result, for instance, if an encrypted message could not be decrypted.)
Under such circumstances, an unsigned receipt (MDN) SHOULD be returned
with the correct "disposition modifier" error value.
- Security Formatting
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This specification relies on the guidelines set forth in
RFCs 2630 [9] and 2633 [10]. The first of these RFCs describes the
Cryptograpic Message Syntax (CMS) and the second contains the S/MIME
Version 3 Message Specification describing a MIME container for
CMS objects. Whenever the term S/MIME is used in this document,
it refers to Version 3 as described therein.
- Hash function, message digest choices
When a signature is used, it is RECOMMENDED that the SHA-1 hash
algorithm be used for all outgoing messages; however, both MD5
and SHA-1 MUST be supported for incoming messages.
- Permutation Summary
In summary, the following twelve security permutations are possible
in any given trading relationship:
1. Sender sends un-encrypted data, does NOT request a receipt.
2. Sender sends un-encrypted data, requests an unsigned receipt.
The receiver sends back the unsigned receipt.
3. Sender sends un-encrypted data, requests a signed receipt. The
receiver sends back the signed receipt.
4. Sender sends encrypted data, does NOT request a receipt.
5. Sender sends encrypted data, requests an unsigned receipt. The
receiver sends back the unsigned receipt.
6. Sender sends encrypted data, requests a signed receipt. The
receiver sends back the signed receipt.
7. Sender sends signed data, does NOT request a receipt.
8. Sender sends signed data, requests an unsigned receipt. Receiver
sends back the unsigned receipt.
9. Sender sends signed data, requests a signed receipt. Receiver
sends back the signed receipt.
10. Sender sends encrypted and signed data, does NOT request a
receipt.
11. Sender sends encrypted and signed data, requests an unsigned
receipt. Receiver sends back the unsigned receipt.
12. Sender sends encrypted and signed data, requests a signed
receipt. Receiver sends back the signed receipt. This case
represents the Secure Transmission Loop described above.
2.4.2.2 Compression options
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The AS3 specification supports compression of transmitted data directly
through the application of RFC 3274. Implementation details may be
found in that RFC and in Harding's draft, "Compressed Data for EDIINT",
currently on a parallel standards track.
3. Referenced RFC's and their contribution
3.1 RFC 959: File Transfer Protocol [3]
RFC 959 specifies how data is transferred using the File Transfer
Protocol (FTP)
3.2 RFC 2228: FTP Security Extensions [4]
This RFC describes a framework for providing security services to
FTP.
3.3 RFC 1847: MIME Security Multiparts [7]
This document defines security multiparts for MIME:
multipart/encrypted and multipart/signed.
3.4 RFC 1892: Multipart/report [12]
RFC 1892 defines the use of the multipart/report content type, upon
which RFC 2298 builds to define the Message Disposition Notification.
3.5 RFC 1767: EDI Content [2]
This RFC defines the use of content type "application" for ANSI X12
(application/EDI-X12), EDIFACT (application/EDIFACT) and mutually
defined EDI (application/EDI-Consent).
3.6 RFC 2045, 2046, and 2049: MIME [1]
These are the basic MIME standards, upon which all MIME related
RFCs build, including this one. Key contributions include definition
of "content type", "sub-type" and "multipart", as well as encoding
guidelines, which establishes 7-bit US-ASCII as the canonical
character set to be used in Internet messaging.
3.7 RFC 2298: Message Disposition Notification [6]
This Internet RFC defines how a Message Disposition Notification (MDN)
is requested, as well as the format and syntax of the MDN. The MDN is
the vehicle used by this specification to provide both signed and
unsigned receipts.
3.8 RFC 2630:CMS[9] and 2633 S/MIME Version 3 Message Specifications[10].
This specification describes how MIME shall carry Cryptographic Message
Syntax (CMS) Objects.
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3.9 RFC 2632: S/MIME Version 3 Certificate Handling [11]
RFC 2632 describes certificate handling in the context of CMS and S/MIME.
3.10 RFC 3274: Compressed Data Content Type for Cryptographic Message
Syntax (CMS) [17]
This specification provides a mechanism to wrap compressed data within a
CMS object.
3.11 RFC 3023: XML Media Types [16]
This RFC defines the use of content type "application" for XML. Note
that while conforming implementations SHOULD support the expanded syntax
that RFC 3023 introduces for the "+xml" suffix, no support for external
parsed entity types is anticipated (as it adds significant complexity to
signature processing).
4. Structure of an AS3 message
4.1 Introduction
The basic structure of AS3 messages comprises MIME encapsulated data
with both customary MIME headers and a few additional AS3-specific outer
headers. The structures below are described hierarchically in terms of
which RFCs have been applied to form the specific structure. The reader
is referred directly to the referenced RFCs for implementation details.
Any additional restrictions imposed by this AS are specifically discussed
in the sections which follow.
4.2 Structure of an Internet EDI MIME message
No encryption, no signature
-RFC822/2045
-RFC1767/RFC2376 (application/EDIxxxx or /xml)
No encryption, signature
-RFC822/2045
-RFC1847 (multipart/signed)
-RFC1767/RFC2376 (application/EDIxxxx or /xml)
-RFC2633 (application/pkcs7-signature)
Encryption, no signature
-RFC822/2045
-RFC2633 (application/pkcs7-mime)
-RFC1767/RFC2376 (application/EDIxxxx or /xml)(encrypted)
Encryption, signature
-RFC822/2045
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-RFC2633 (application/pkcs7-mime)
-RFC1847 (multipart/signed)(encrypted)
-RFC1767/RFC2376 (application/EDIxxxx or /xml)(encrypted)
-RFC2633 (application/pkcs7-signature)(encrypted)
MDN, no signature
-RFC822/2045
-RFC2298 (message/disposition-notification)
MDN, signature
-RFC822/2045
-RFC1847 (multipart/signed)
-RFC2298 (message/disposition-notification)
-RFC2633 (application/pkcs7-signature)
While all MIME content types SHOULD be supported.
The following MIME content types MUST be supported:
Content-type: multipart/signed
Content-Type: multipart/report
Content-type: message/disposition-notification
Content-Type: application/PKCS7-signature
Content-Type: application/PKCS7-mime
Content-Type: application/EDI-X12
Content-Type: application/EDIFACT
Content-Type: application/edi-consent
Content-Type: application/XML
5. AS3-specific Headers
5.1 AS3-From and AS3-To headers
The AS3-From and AS3-To headers have been provided to assist the sender
and the recipient of an EC document to identify each other:
AS3-From: < AS3-name >
AS3-To: < AS3-name >
These headers contain textual values, described by the ABNF below,
identifying the sender/receiver of a data exchange. A value may
be company specific (e.g., a DUNS number), or it may be simply some
string mutually acceptable to both trading partners used to identify
each to the other.
AS3-text = "!" / ; printable ASCII characters
%d35-91 / ; except double-quote (%d34)
%d93-126 ; or backslash (%d92)
AS3-qtext = AS3-text / SP ; allow space only in quoted text
AS3-quoted-pair = "\" DQUOTE / ; \" or
"\" "\" ; \\
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AS3-quoted-name = DQUOTE 1*128( AS3-qtext /
AS3-quoted-pair) DQUOTE
AS3-atomic-name = 1*128AS3-text
AS3-name = AS3-atomic-name / AS3-quoted-name
The AS3-From header value and the AS3-To header value MUST each be an
AS3-name comprising 1 to 128 printable ASCII characters. The header
MUST NOT be folded, and the value for each of these headers
is case-sensitive.
The AS3-quoted-name SHOULD be used only if the AS3-name does not
conform to AS3-atomic-name.
The AS3-To and AS3-From header fields MUST be present in all AS3
messages and AS3 MDN's.
Implementations which map entities such as EDI identifiers/qualifiers
to AS3 identifiers may choose to constrain the set of AS3-To/AS3-From
text values to a subset of the full set defined above but may not
extend that set.
If either the AS3-From or the AS3-To or the association of the two header
values is determined to be invalid or unknown to the receiving system,
the receiving system MAY respond with an unsigned MDN containing an
explanation of the error if the sending system requested an MDN, but
it is not required to return an MDN under those circumstances.
5.2 AS3-Version header
The AS3-Version header is a header which is required only if the value
of the header is not "1.0". Its purpose is to allow systems to
determine which version of this specification, should the specification
evolve over time, the sender of a document has used to package the
document.
AS3-Version: 1*DIGIT . 1*DIGIT
6. FTP Considerations
6.1 FTP Security Requirements
FTP has long been viewed as an insecure protocol primarily because of
its use of cleartext authentication [FTP]. This is addressed by RFC
2228, and the use of one of the security mechanisms described therein
is strongly encouraged. Specifically, conforming implementations of
AS3 SHALL employ FTP client/servers that support the AUTH command
described within [SFTP]. While any authentication mechanism based upon
[SFTP] MAY be utilized, AUTH TLS (as described in [MURRAY]) MUST be
supported.
6.2 Large file transfers
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Large files are handled correctly by the TCP layer. However, there is
the mechanism for compressing data referenced in section 2.4.2.2
above which efficiently reduces transmission requirements for many data
types (including both XML and traditional EDI data.) Additionally, some
FTP implementations support compression as well.
6.3 MIME Considerations for FTP
6.3.1 Required/Optional Headers
An AS3 message MUST contain the following outer headers:
AS3-To
AS3-From
Date
Message-ID
Content-Type
An AS3 message OPTIONALLY MAY contain the following outer headers:
Subject
AS3-Version (assumed to be 1.0 if not present)
Content-Length
An AS3 message requesting a receipt MUST contain a
Disposition-Notification-To header and MAY contain a
Disposition-Notification-Options header(if the receipt is to be signed)
Additional headers MAY be present but are ignored.
6.3.2 Content-Transfer-Encoding Not Used
FTP defines several data structures and character encodings via the
STRU[cture] and TYPE commands. AS3 requires the file-structure (default)
and the image type. The Content-Transfer-Encoding header SHOULD NOT be
used; if the header is present, it MUST have a value of binary or 8-bit,
and the absence of this header MUST NOT result in transaction failure.
Content transfer encoding of MIME parts within the AS3 message are
similarly constrained.
6.3.3 Epilogue Must Be Empty
A MIME message containing an epilogue [MIME] SHALL NOT be used.
6.3.4 Message-Id and Original-Message-Id
Message-Id and Original-Message-Id are formatted as defined in
section 3.6.4 of RFC2822 [15]: "<" id-left "@" id-right ">".
Message-Id length is a maximum of 998 characters. Message-Id
SHOULD be globally unique, id-right should be something unique
to the sending host environment (e.g. a host name). When sending
a message, always include the angle brackets. Angle brackets are
not part of the Message-Id value.
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NOTE: When creating the Original-Message-Id header in an MDN,
always use the exact syntax contained in the original
message: do not strip or add "angle brackets".
7. Structure and Processing of an MDN Message
7.1 Introduction
In order to support non-repudiation of receipt, a signed receipt,
based on digitally signing a message disposition notification, is to
be implemented by a receiving trading partner's UA. The message
disposition notification specified by RFC 2298 is digitally signed by
a receiving trading partner as part of a multipart/signed MIME
message.
The following support for signed receipts is REQUIRED:
1) The ability to create a multipart/report;
where the report-type = disposition-notification.
2) The ability to calculate a message integrity check (MIC) on the
received message. The calculated MIC value will be returned to the
sender of the message inside the signed receipt.
3) The ability to create a multipart/signed content with the message
disposition notification as the first body part, and the signature
as the second body part.
4) The ability to return the signed receipt to the sending trading
partner.
The signed receipt is used to notify a sending trading partner that
requested the signed receipt that:
1) The receiving trading partner acknowledges receipt of the sent EC
Interchange.
2) If the sent message was signed, then the receiving trading partner
has authenticated the sender of the EC Interchange.
3) If the sent message was signed, then the receiving trading partner
has verified the integrity of the sent EC Interchange.
Regardless of whether the EDI/EC Interchange was sent in S/MIME format
or not, the receiving trading partner's UA MUST provide the following
basic processing:
1) If the sent EDI/EC Interchange is encrypted, then the encrypted
symmetric key and initialization vector (if applicable) is
decrypted using the receiver's private key.
2) The decrypted symmetric encryption key is then used to decrypt the
EDI/EC Interchange.
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3) The receiving trading partner authenticates signatures in a message
using the sender's public key.
The authentication algorithm performs the following:
a) The message integrity check (MIC or Message Digest), is decrypted
using the sender's public key.
b) A MIC on the signed contents (the MIME header and encoded EDI
object, as per RFC 1767) in the message received is calculated
using the same one-way hash function that the sending trading
partner used.
c) The MIC extracted from the message that was sent, and the MIC
calculated using the same one-way hash function that the sending
trading partner used is compared for equality.
4) The receiving trading partner formats the MDN and sets the
calculated MIC into the "Received-content-MIC" extension field.
5) The receiving trading partner creates a multipart/signed MIME
message according to RFC 1847.
6) The MDN is the first part of the multipart/signed message, and the
digital signature is created over this MDN, including its MIME
headers.
7) The second part of the multipart/signed message contains the
digital signature. The "protocol" option specified in the second
part of the multipart/signed is as follows: S/MIME:
protocol = "application/pkcs7-signature"
8) The signature information is formatted according to S/MIME
specifications. The EC Interchange and the RFC 1767 MIME EDI
content header can actually be part of a multi-part MIME
content-type. When the EDI Interchange is part of a multi-part
MIME content-type, the MIC MUST be calculated across the entire
multi-part content, including the MIME headers.
The signed MDN, when received by the sender of the EDI Interchange can
be used by the sender:
1) As an acknowledgment that the EDI Interchange sent, was delivered
and acknowledged by the receiving trading partner. The receiver
does this by returning the original-message-id of the sent message
in the MDN portion of the signed receipt.
2) As an acknowledgment that the integrity of the EDI Interchange was
verified by the receiving trading partner. The receiver does this
by returning the calculated MIC of the received EC Interchange
(and 1767 MIME headers) in the "Received-content-MIC" field of the
signed MDN.
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3) As an acknowledgment that the receiving trading partner has
authenticated the sender of the EDI Interchange.
4) As a non-repudiation of receipt when the signed MDN is successfully
verified by the sender with the receiving trading partner's public
key and the returned MIC value inside the MDN is the same as the
digest of the original message.
7.2 Message Disposition Notifications (MDN)
The AS3-MDNs are returned on a separate FTP TCP/IP
connection and are a response to an AS3 message.
The following diagram illustrates the delivery of an
AS3-MDN delivery:
AS3-MDN
[S] ----( connect )----> [R] [FTP Server]
[S] ----( send )-------> [R] [AS3-Message]
[S] ----( disconnect )-> [R] [FTP Server]
[S] <---( connect )----- [R] [FTP Server]
[S] <---( send )-------- [R] [AS3-MDN]]
[S] <---( disconnect )-- [R] [FTP Server]
7.3 Requesting a signed receipt
Message Disposition Notifications are requested as per RFC 2298. A
request that the receiving user agent issue a message disposition
notification is made by placing the following header into the message
to be sent:
MDN-request-header = "Disposition-notification-to" ":" ftp-url
This syntax is a residual of the use of MDN's in a SMTP transfer. Since
this specification is adjusting the functionality from SMTP to FTP and
retaining as much as possible from the [5] functionality, the
ftp-url must be present.
The ftp-url field is specified as an RFC 1738
<URL:ftp://host.com:port/url-path>, and while it MUST be present,
it may be ignored if the ftp-url points to an unknown location. If the
ftp-url points to an unknown location it is RECOMMENDED that the mdn is
returned back to a known ftp-url for the sender of the received message.
For requesting MDN based receipts, the originator supplies the syntax of
extension headers that precede the message body.
The header "tags" are as follows:
A Disposition-notification-to header is added to indicate that a message
disposition notification is requested. This header is specified in [6].
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A Message-ID header is added to support message reconciliation, so that
an Original-Message-Id value can be returned in the body part of MDN.
Other headers, especially "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.
Disposition-notification-options identifies characteristics of message
Disposition notification in accordance with [6].
EXAMPLE:
Disposition-notification-to: // Requests the MDN
ftp://host:port/inbox // Location to return MDN
Disposition-notification-options: // The signing options for MDN
signed-receipt-protocol=optional, pkcs7-signature;
signed-receipt-micalg=optional, sha1, md5
Disposition-notification-options syntax:
Disposition-notification-options =
"Disposition-Notification-Options" ":"
disposition-notification-parameters
where
disposition-notification-parameters =
parameter *(";" parameter)
where
parameter = attribute "=" importance ", " 1#value"
where
importance = "required" | "optional"
So the Disposition-notification-options string could be:
signed-receipt-protocol=optional, <protocol symbol>;
signed-receipt-micalg=optional, <micalg1>, <micalg2>,...;
The currently supported value for <protocol symbol> is "pkcs7-signature"
for the S/MIME detached signature format.
The currently supported values for MIC algorithm <micalg> values are:
Algorithm Value
Used
-------- -------
MD5 md5
SHA-1 sha1
Receiving agents SHOULD be able to recover gracefully from a <micalg>
parameter value that they do not recognize.
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The semantics of the "signed-receipt-protocol" parameter is as follows:
1) The "signed-receipt-protocol" parameter is used to request a signed
receipt from the recipient trading partner. The
"signed-receipt-protocol" parameter also specifies the format in
which the signed receipt should be returned to the requester.
The "signed-receipt-micalg" parameter is a list of MIC algorithms
preferred by the requester for use in signing the returned receipt
and calculating the micalg in the Received-content-MIC header.
The list of MIC algorithms should be honored by the recipient from
left to right. Both the "signed-receipt-protocol" and the
"signed-receipt-micalg" option parameters are REQUIRED when
requesting a signed receipt.
2) The "importance" attribute of "Optional" is defined in the RFC 2298
section 2.2 and has the following meaning:
Parameters with an importance of "Optional" permit a UA that does not
understand the particular options parameter to still generate a MDN
in response to a request for a MDN. A UA that does not understand the
"signed-receipt-protocol" parameter, or the "signed-receipt-micalg"
will obviously not return a signed receipt.
The importance of "Optional" is used for the signed receipt
parameters because it is RECOMMENDED that an MDN be returned to the
requesting trading partner even if the recipient could not sign it.
The returned MDN will contain information on the disposition of the
message as well as why the MDN could not be signed. See the
Disposition field in section 7.5 for more information.
Within an EDI trading relationship, if a signed receipt is expected
and is not returned, then the validity of the transaction must be
determined by the trading partners. Typically, if a signed receipt is
required by the trading relationship and is not received, the
transaction will likely not be considered valid.
7.3.1 Signed Receipt Considerations
The method used to request a receipt or a signed receipt is defined in
RFC 2298, "An Extensible Message Format for Message Disposition
Notifications".
The "rules" for processing a receipt-request follow:
1) When a receipt is requested, explicitly specifying that the receipt be
signed, then the receipt MUST be returned with a signature unless
conditions (2) or (3) below are applicable.
2) When a receipt is requested, explicitly specifying that the receipt be
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signed, but the recipient cannot support either the requested protocol
format, or requested MIC algorithms, then either a signed or unsigned
receipt SHOULD be returned.
3) When a receipt is requested, explicitly specifying that the receipt be
signed, but the recipient is unable to compute the digest (e.g., message
was encrypted and recipient unable to decrypt), then the recipient SHOULD
NOT return "Received-Content-MIC" in the MDN to the requestor. If the
MDN sets the disposition (e.g., "processed/error: decryption-failed")
appropriately, then the "Received-Content-MIC" may be returned but the
value must be discarded.
4) When a signature is not explicitly requested, or if the signed receipt
request parameter is not recognized by the UA, then no receipt, an
unsigned receipt, or a signed receipt MAY be returned by the
recipient.
5) If a message is received without a request for a receipt, then a receipt
(signed or unsigned) MAY be returned.
The "Received-content-MIC" MUST be calculated as follows:
- For any signed messages, the MIC to be returned is calculated on
the RFC1767 MIME header and content. Canonicalization as specified
in RFC 1848 MUST be performed before the MIC is calculated, since
the sender requesting the signed receipt was also REQUIRED to
canonicalize.
- For encrypted, unsigned messages, the MIC to be returned is
calculated on the decrypted RFC 1767 MIME header and content. The
content after decryption MUST be canonicalized before the MIC is
calculated.
- For unsigned, unencrypted messages, the MIC MUST be calculated
over the message contents prior to Content-Tranfer-Encoding and
without the MIME or any other RFC 822 headers, since these are
sometimes altered or reordered by MTAs.
7.4 MDN Format and value
This section defines the format of the AS3 Message Disposition
Notification (AS3-MDN).
7.4.1 AS3-MDN General Formats
The AS3-MDN follows the MDN specification [6] except where noted in
this section. The modified entity definitions in this document use
the vertical-bar character, '|', to denote a logical "OR"
construction. Refer to RFC 2045 for format of MIME-message-headers.
The format of the AS3-MDN is
AS3-MDN = *(( MIME-message-headers | entity-headers )CRLF)
CRLF
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AS3-MDN-body
AS3-MDN-body =
AS3-signed-MDN-body | AS3-unsigned-MDN-body
7.4.2 AS3-MDN Construction
The AS3-MDN-body is formatted as a MIME multipart/report with a
report-type of "disposition-notification".
When unsigned, the transfer-layer ( "outermost" ) entity-headers of
the AS3-MDN contain the content-type header that specifies a
content-type of "multipart/report" and parameters indicating the
report-type, and the value of the outermost multipart boundary.
When the AS3-MDN is signed, the transfer-layer ( "outermost" )
entity-headers of the AS3-MDN contain a content-type header that
specifies a content-type of "multipart/signed" and parameters
indicating the algorithm used to compute the message digest, the
signature formatting protocol ( e.g. pkcs7-signature ), and the
value of the outermost multipart boundary. The first part of the
MIME multipart/signed message is an embedded MIME multipart/report
of type "disposition-notification". The second part of the
multipart/signed message contains a MIME application/pkcs7-signature
message.
The first part of the MIME multipart/report is a "human-readable"
portion that contains a general description of the message
disposition. The second part of the MIME multipart/report is a
"machine-readable" portion that is defined as
AS3-disposition-notification-content =
[ reporting-ua-field CRLF ]
[ mdn-gateway-field CRLF ]
[ original-recipient-field CRLF ]
final-recipient-field CRLF
[ original-message-id-field CRLF ]
AS3-disposition-field CRLF
*( failure-field CRLF )
*( error-field CRLF )
*( warning-field CRLF )
*( extension-field CRLF )
[ AS3-received-content-MIC-field CRLF ]
It is noted that several of the optional fields defined by RFC 2298
and shown above are not relevant to a point-to-point transport such
as FTP and would not normally appear in an AS3 MDN.
7.4.3 AS3-MDN Fields
The rules for constructing the AS3-disposition-notification-content
are identical to the rules for constructing the
disposition-notification-content as defined in section 7 of RFC
2298 [6] except that the RFC 2298 disposition-field has
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been replaced with the AS3-disposition-field and that the
AS3-received-content-MIC field has been added. The differences
between the RFC 2298 disposition-field and the
AS3-disposition-field are described below. Where
there are differences between this document and RFC 2298, those
entity names have been changed by prepending "AS3-". Entities below
that do not differ from RFC 2298 are not necessarily further
defined in this document.
Refer to RFC 2298 for AS3-MDN entities that are not further defined
in this document.
AS3-disposition-field = "Disposition" ":" disposition-mode ";"
AS3-disposition-type [ '/' AS3-disposition-modifier ]
disposition-mode = action-mode "/" sending-mode
action-mode = "manual-action" | "automatic-action"
sending-mode = "MDN-sent-manually" | "MDN-sent-automatically"
AS3-disposition-type = "processed" | "failed"
AS3-disposition-modifier = ( "error" | "warning" ) |
AS3-disposition-modifier-extension
AS3-disposition-modifier-extension =
"error: authentication-failed" |
"error: decompression-failed" |
"error: decryption-failed" |
"error: insufficient-message-security" |
"error: integrity-check-failed" |
"error: unexpected-processing-error" |
"warning: " AS3-MDN-warning-description |
"failure: " AS3-MDN-failure-description
AS3-MDN-warning-description = *( TEXT )
AS3-MDN-failure-description = *( TEXT )
AS3-received-content-MIC-field =
"Received-content-MIC" ":" encoded-message-digest
"," digest-alg-id CRLF
encoded-message-digest =
1*( 'A'-Z' | 'a'-'z' | '0'-'9' | '/' | '+' ) 0*3( '=' )
( i.e. base64( message-digest ) )
digest-alg-id = "sha1" | "md5"
The "Received-content-MIC" extension field is set after the
integrity of the received message is verified. The MIC is the
base64-encoded message-digest computed over the received message
with a hash function. This field is required for signed receipts
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but optional for unsigned receipts. For details defining the
specific content over which the message-digest is to be computed,
see Section 7.3.1 of this document.
The algorithm used to calculate the message digest MUST be the
same as the "micalg" value used by the sender in the
multipart/signed message. When no signature is received the
message-digest MUST be calculated using the algorithm specified
by the "micalg" value in the Disposition-Notification-Options header.
When no signature is received and no micalg parameter is provided,
then the SHA-1 algorithm MUST be used to calculate the digest.
This field is set only when the contents of the message are
processed successfully. This field is used in conjunction with
the recipient's signature on the MDN in order for the sender to
verify non-repudiation of receipt.
AS3-MDN field names ( e.g. "Disposition:", "Final-Recipient:")
are case-insensitive ( cf. RFC 2298, 3.1.1 ).
AS3-MDN action-modes, sending-modes, AS3-disposition-types, and
AS3-disposition-modifier values that are defined above, and
user-supplied *( TEXT ) values are also case-insensitive. AS3
implementations MUST NOT make assumptions regarding the values
supplied for AS3-MDN-warning-description,
AS3-MDN-failure-description nor for the values of any (optional)
error, warning, or failure fields.
7.4.4 Additional AS3-MDN Programming Notes
1. Unlike SMTP, for FTP transactions, Original-Recipient and
Final Recipient SHOULD NOT be different. The value in
Original-Message-ID MUST match the original Message-ID
header value.
2. Refer to RFC 1892 and RFC 2298 for the formatting of the
content-type entity-headers for the MDN.
3. Use an action-mode of "automatic-action" when the disposition
described by the disposition type was a result of an automatic
action, rather than an explicit instruction by the user for
this message.
4. Use an action-mode of "manual-action" when the disposition
described by the disposition type was a result of an explicit
instruction by the user rather than some sort of automatically
performed action.
5. Use a sending-mode of "MDN-sent-automatically" when the MDN is
sent because the UA had previously been configured to do so.
6. Use a sending-mode of "MDN-sent-manually" when the user
explicitly gave permission for this particular MDN to be sent.
7. The sending-mode "MDN-sent-manually" is ONLY meaningful with
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"manual-action", not with "automatic-action".
8. The "failed" disposition type MAY NOT be used for the
situation in which there is some problem in processing the
message other than interpreting the request for an MDN.
The "processed" or other disposition type with appropriate
disposition modifiers is to be used in such situations.
7.5 Disposition Mode, Type, and Modifier
7.5.1 Disposition Mode Overview
This section will provide a brief overview of how processed,
error, failure, and warnings are used.
7.5.2 Successful Processing status indication
When the request for a receipt or signed receipt, and the received
message contents are successfully processed by the receiving EDI
UA, a receipt or MDN SHOULD be returned with the
"disposition-type" set to 'processed'. When the MDN is sent
automatically by the EDI UA, and there is no explicit
way for a user to control the sending of the MDN, then the first
part of the "disposition-mode" should be set to "automatic-action".
When the MDN is being sent under user configurable control, then
the first part of the "disposition-mode" should be set to
"manual-action". Since a request for a signed receipt should always
be honored, the user MUST not be allowed to configure the UA to not
send a signed receipt when the sender requests one.
The second part of the "disposition-mode" is set to
"MDN-sent-manually" if the user gave explicit permission for the
MDN to be sent. Again, the user MUST not be allowed to explicitly
refuse to send a signed receipt when the sender requests one. The
second part of the "disposition-mode" is set to
"MDN-sent-automatically" whenever the EDI UA sends the MDN
automatically, regardless of whether the sending was under a
user's, administrator's, or under software control.
Since EDI content is generally handled automatically by the EDI UA,
a request for a receipt or signed receipt will generally return the
following in the "disposition-field":
Disposition: automatic-action/MDN-sent-automatically; processed
Note this specification does not restrict the use of the
"disposition-mode" to just automatic actions. Manual actions are
valid as long as it is kept in mind that a request for a signed
receipt MUST be honored.
7.5.3 Unsuccessful processed Content
The request for a signed receipt requires the use of two
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"disposition-notification-options", which specify the protocol
format of the returned signed receipt, and the MIC algorithm used
to calculate the MIC over the message contents. The
"disposition-field" values that should be used in the case where
the message content is being rejected or ignored, for instance if
the EDI UA determines that a signed receipt cannot be returned
because it does not support the requested protocol format, so the
EDI UA chooses not to process the message contents itself, should
be specified in the MDN "disposition-field" as follows:
Disposition: "disposition-mode"; failed/Failure: unsupported Format
The "failed" AS3-disposition-type should be used when a failure
occurs that prevents the proper generation of an MDN.
For example, this disposition-type would apply if the sender of the
message requested the application of an unsupported
message-integrity-check (MIC) algorithm.
The "failure:" AS3-disposition-modifier-extension should be used
with an implementation-defined description of the failure.
Further information about the failure may be contained in a
failure-field. The syntax of the "failed" "disposition-type" is
general, allowing the sending of any textual information along with
the "failed" "disposition-type". Implementations WILL support any
printable textual characters after the Failure disposition-type.
For use in Internet EDI, the following "failed" values are
pre-defined and MUST be supported:
"Failure: unsupported format"
"Failure: unsupported MIC-algorithms"
7.5.4 Unsuccessful Non-Content Processing
When errors occur processing the received message other than
content, the "disposition-field" should be set to the "processed"
"disposition-type" value and the "error" "disposition-modifier" \
value.
The "error" AS3-disposition-modifier with the "processed"
disposition-type should be used to indicate that an error of some
sort occurred that prevented successful processing of the message.
Further information may be contained in an error-field.
An "error:" AS3-disposition-modifier-extension should be used to
combine the indication of an error with a pre-defined description
of a specific, well-known error. Further information about the
error may be contained in an error-field.
For use in Internet EDI, the following "error"
"disposition-modifier" values are defined:
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"Error: decryption-failed" - the receiver could not decrypt the
message contents.
"Error: authentication-failed" - the receiver could not
authenticate the sender.
"Error: integrity-check-failed" - the receiver could not verify
content integrity.
"Error: insufficient-message-security" - the security level of the
message did not match the
agreed level between TPs.
"Error: decompression-failed" - the receiver could not decompress
the message contents.
"Error: unexpected-processing-error" - a catch-all for any
additional processing
errors.
An example of how the "disposition-field" would look when other
than content processing errors are detected is as follows:
EXAMPLE
Disposition: "disposition-mode";
processed/Error: decryption-failed
7.5.5 Processing Warnings
Situations arise in EDI where even if a trading partner cannot be
authenticated correctly, the trading partners still agree to
continue processing the EDI transactions. Transaction reconciliation
is done between the trading partners at a later time. In the content
processing warning situations as described above, the
"disposition-field' SHOULD be set to the "processed"
"disposition-type" value, and the "warning" "disposition-modifier"
value.
The "warning" AS3-disposition-modifier should be used with the
"processed" disposition-type to indicate that the message was
successfully processed but that an exceptional condition occurred.
Further information may be contained in a warning-field.
A "warning:" AS3-disposition-modifier-extension should be used to
combine the indication of a warning with an implementation-defined
description of the warning. Further information about the warning
may be contained in an warning-field.
For use in Internet EDI, the following "warning"
"disposition-modifier" values are defined:
"Warning: authentication-failed, processing continued"
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An example of how the "disposition-field" would look when other than
content processing warnings are detected is as follows:
EXAMPLE
Disposition: "disposition-mode"; processed/Warning:
authentication-failed, processing continued
8. Public key certificate handling
In the near term, the exchange of public keys and certification of
these keys must be handled as part of the process of establishing a
trading partnership. The UA and/or EDI application interface must
maintain a database of public keys used for encryption or
signatures, in addition to the mapping between EDI trading partner
ID and FTP URL/URI. The procedures for establishing a trading
partnership and configuring the secure EDI messaging system might
vary among trading partners and software packages.
X.509 certificates are REQUIRED. It is RECOMMENDED that trading
partners self-certify each other if an agreed upon certification
authority is not used. This applicability statement does NOT require
the use of a certification authority.
The use of a certification authority is therefore OPTIONAL.
Certificates may be self-signed. It is RECOMMENDED that when trading
partners are using S/MIME, that they also exchange public key
certificates using the recommendations specified in the S/MIME
Version 3 Message Specification.
The message formats and S/MIME conformance requirements for
certificate exchange are specified in this document. In the long
term, additional Internet-EDI standards may be developed to simplify
the process of establishing a trading partnership, including the
third party authentication of trading partners, as well as
attributes of the trading relationship.
9. Security Considerations
This entire document is concerned with secure transport of business
to business data, and considers both privacy and authentication
issues.
Extracted from S/MIME Version 2 Message Specification: 40-bit
encryption is considered weak by most cryptographers. Using weak
cryptography offers little actual security over sending plaintext.
However, other features of S/MIME, such as the specification of
tripleDES or AES and the ability to announce stronger cryptographic
capabilities to parties with whom you communicate, allow senders to
create messages that use strong encryption. Using weak cryptography
is never recommended unless the only alternative is no cryptography.
When feasible, sending and receiving agents should inform senders
and recipients the relative cryptographic strength of messages.
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Extracted from S/MIME Version 3 Certificate Handling (ref [11]):
When processing certificates, there are many situations where the
processing might fail. Because the processing may be done by a user
agent, a security gateway, or other program, there is no single way
to handle such failures. Just because the methods to handle the
failures have not been listed, however, the reader should not assume
that they are not important. The opposite is true: if a certificate
is not provably valid and associated with the message, the processing
software should take immediate and noticeable steps to inform the end
user about it.
Some of the many places where signature and certificate checking
might fail include:
- no certificate chain leads to a trusted CA
- no ability to check the CRL for a certificate
- an invalid CRL was received
- the CRL being checked is expired
- the certificate is expired
- the certificate has been revoked
There are certainly other instances where a certificate may be
invalid, and it is the responsibility of the processing software to
check them all thoroughly, and to decide what to do if the check
fails.
The following certificate types MUST be supported.
With URL
Without URL
Self Certified
Certification Authority Certified
The complete certification chain MUST be included in all
certificates. All certificate verifications MUST "chain to root".
Additionally, the certificate hash should match the hash recomputed
by the receiver.
10. Acknowledgements
To be completed.
11. References
[1] 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.
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N. Borenstein, N.Freed, "Multipurpose Internet Mail
Extensions (MIME)
Part Five: Conformance Criteria and Examples", RFC 2049 ,
December 02, 1996.
[2] D. Crocker, "MIME Encapsulation of EDI Objects", RFC 1767,
March 2, 1995.
[3] J. Postel, J. Reynolds,
"FILE TRANSFER PROTOCOL (FTP)", RFC 959, October 1985.
[4] M. Horowitz, S. Lunt, "FTP Security Extensions", RFC 2228,
October, 1997
[5] T. Harding, R. Drummond, C. Shih, "Peer-to-Peer MIME-based Secure
Business Data Interchange", RFC 3335, September 2002.
[6] R. Fajman, "An Extensible Message Format for Message Disposition
Notifications", RFC 2298, March 1998.zz
[7] J. Galvin, S. Murphy, S. Crocker, N. Freed, "Security Multiparts
for MIME:
Multipart/Signed and Multipart/Encryptezd", RFC 1847, Oct. 3, 1995
[8] J. Postel, "Simple Mail Transfer Protocozl", STD 10, RFC 821,
August 1, 1982.
[9] R. Housley, "Cryptographic Message Syntax", RFC 2630, June 1999.
[10] B. Ramsdell, "S/MIME Version 3 Message Specification;
RFC 2633 June 1999.
[11] B. Ramsdell, "S/MIME Version 3 Certificate Handling", RFC 2632,
June 1999
[12] G. Vaudreuil, "The Multipart/Report Content Type for the
Reporting of Mail System Administrative Messages", RFC 1892,
March 15, 1996.
[13] T. Dierks,C. Allen, "The TLS Protocol Version 1.0" RFC 2246,
March 1999.
[14] D. Crocker, "Standard for the Format of ARPA Internet Text
Messages", STD 11, RFC 822, August 13, 1982.
[15] P. Resnick, "Internet Message Format", RFC 2822, April 2001.
[16] E. Whitehead, M. Murata, "XML Media Types", RFC 2376, July 1998.
[17] P. Gutmann, "Compressed Data Content Type for Cryptographic Message
Syntax (CMS)", RFC 3274, June 2002
12. Authors' Addresses
Terry Harding
tharding@cyclonecommerce.com
Cyclone Commerce
8388 E. Hartford Drive, Suite 100
Scottsdale, AZ 85255 USA
Richard Scott
rscott@cyclonecommerce.com
Cyclone Commerce
8388 E. Hartford Drive, Suite 100
Scottsdale, AZ 85255 USA
Appendices
A. Message Examples
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NOTE: All examples are provided as an illustration only, and are not
considered part of the protocol specification. If an example
conflicts with the protocol definitions specified above or with
that of a referenced RFC, the example is wrong.
A.1 Signed message requesting a signed receipt
Date: Wed, 31 Jul 2002 13:34:50 GMT
AS3-Version: 1.0
AS3-From: cyclone
AS3-To: "trading partner"
Message-Id: <200207310834482A70BF63@host.com>
Disposition-Notification-To: ftp://host:port/mdnbox
Disposition-Notification-Options: signed-receipt-
protocol=optional,pkcs7-signature;
signed-receipt-micalg=optional,sha1
Content-Type: multipart/signed; boundary="as3BouNdary1as3";
protocol="application/pkcs7-signature"; micalg=sha1
Content-Length: 3075
--as3BouNdary1as3
Content-Type: application/edi-x12
Content-Disposition: Attachment; filename=rfc1767.dat
[ISA ...EDI transaction data...IEA...]
--as3BouNdary1as3
Content-Type: application/pkcs7-signature
[omitted binary pkcs7 signature data]
--as3BouNdary1as3--
A.2 MDN for Message A.1 Above
Date: Wed, 31 Jul 2002 13:34:50 GMT
From: "trading partner"
AS3-To: cyclone
AS3-Version: 1.0
Message-ID: <709700825.1028122454671.JavaMail@ediXchange>
Content-Type: multipart/signed; micalg=sha1;
protocol="application/pkcs7-signature";
boundary="----=_Part_57_648441049.1028122454671"
Content-Length: 1024
------=_Part_57_648441049.1028122454671
& Content-Type: multipart/report;
& Report-Type=disposition-notification;
& boundary="----=_Part_56_1672293592.1028122454656"
&
&------=_Part_56_1672293592.1028122454656
&Content-Type: text/plain
&Content-Transfer-Encoding: 7bit
&
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FTP Transport for Secure P2P Business Data Interchange March 03, 2004
&MDN for -
& Message ID: <200207310834482A70BF63@host.com>
& From: cyclone
& To: "trading partner"
& Received on: 2002-07-31 at 09:34:14 (EDT)
& Status: processed
& Comment: This is not a guarantee that the message has been
& completely processed or understood by the receiving translator
&
&------=_Part_56_1672293592.1028122454656
& Content-Type: message/disposition-notification
& Content-Transfer-Encoding: 7bit
&
& Reporting-UA: AS3 Server
& Original-Recipient: rfc822; "trading partner"
& Final-Recipient: rfc822; "trading partner"
& Original-Message-ID: <200207310834482A70BF63@host.com>
& Received-content-MIC: 7v7F++fQaNB1sVLFtMRp+dF+eG4=, sha1
& Disposition: automatic-action/MDN-sent-automatically; processed
&
&------=_Part_56_1672293592.1028122454656--
------=_Part_57_648441049.1028122454671
Content-Type: application/pkcs7-signature; name=smime.p7s
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=smime.p7s
MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQ
cp24hMJNbxDKHnlB9jTiQzLwSwo+/90Pc87x+Sc6EpFSUYWGAAAAAAAA
------=_Part_57_648441049.1028122454671--
Notes:
1. The lines proceeded with "&" is what the signature is calculated
over.
2. For details on how to prepare the multipart/signed with protocol =
"application/pkcs7-signature" see the "S/MIME Message
Specification, PKCS Security Services for MIME".)
3. Note that the textual first body part of the multipart/report can be
used to include a more detailed explanation of the error conditions
reported by the disposition headers. The first body part of the
multipart/report when used in this way, allows a person to better
diagnose a problem in detail.
4. As specified by RFC 1892 [10], returning the original or portions of
the original message in the third body part of the multipart/report
is not required. This is an optional body part. However, it is
RECOMMENDED that this body part be omitted or left blank.
B. IANA Registration Form
A.1 IANA registration of the signed-receipt-protocol content
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FTP Transport for Secure P2P Business Data Interchange March 03, 2004
disposition parameter
Parameter-name: signed-receipt-protocol
Syntax: See section 7.3 of this document
Specification: See section 7.3 of this document
A.2 IANA registration of the signed-receipt-micalg content
disposition parameter
Parameter-name: signed-receipt-micalg
Syntax: See section 7.3 of this document
Specification: See section 7.3 of this document
A.3 IANA registration of the Received-content-MIC MDN extension
field name
Extension field name: Received-content-MIC
Syntax: See section 7.4.3 of this document
Specification: See section 7.4.3 of this document.
