                              UN/EDIFACT

                UNITED NATIONS STANDARD MESSAGE (UNSM)

          Secure authentication and acknowledgement message




























                                            Message Type : AUTACK
                                            Version      : 4
                                            Release      : V4R1
                                            Contr. Agency: UN

                                            Revision     : 1
                                            Date         : 2001-11-01






SOURCE: Joint Syntax Working Group (JSWG)



                               CONTENTS

          Secure authentication and acknowledgement message

0.   INTRODUCTION

1.   SCOPE

     1.1   Functional definition

     1.2   Field of application

     1.3   Principles

2.   REFERENCES

3.   TERMS AND DEFINITIONS

     3.1   Standard terms and definitions

4.   MESSAGE DEFINITION

     4.1   Data segment clarification

     4.2   Data segment index (alphabetical sequence)

     4.3   Message structure

           4.3.1 Segment table










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For general information on UN standard message types see UN Trade Data
Interchange Directory, UNTDID, Part 4, Section 2.6, UN/ECE UNSM
General Introduction
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0.     INTRODUCTION

       This is a new part, which has been added to ISO 9735. It
       provides an optional capability of securing a batch EDIFACT
       structures i.e. messages, packages, groups or interchanges, by
       means of a secure authentication and acknowledgement message.

1.     SCOPE

       This part of ISO 9735 for EDIFACT security defines the secure
       authentication and acknowledgement message AUTACK.

1.1    Functional Definition

       AUTACK is a message authenticating sent, or providing secure
       acknowledgement of received interchanges, groups, messages or
       packages.
       
       A secure authentication and acknowledgement message can be used
       to:
       
       a)  give secure authentication, integrity or non-repudiation of
       origin to messages, packages, groups or interchanges.
       
       b)  give secure acknowledgement or non-repudiation of receipt
       to secured messages, packages, groups or interchanges.

1.2    Field of Application

       The secure authentication and acknowledgement message (AUTACK)
       may be used for both national and international trade. It is
       based on universal practice related to administration, commerce
       and transport, and is not dependent on the type of business or
       industry.

1.3    Principles

       The applied security procedures shall be agreed to by trading
       partners and specified in an interchange agreement.
       
       The secure authentication and acknowledgement message (AUTACK)
       applies security services to other EDIFACT structures
       (messages, packages, groups or interchanges) and provides
       secure acknowledgement to secured EDIFACT structures. It can be
       applied to combinations of EDIFACT structures that need to be
       secured between two parties.
       
       The security services are provided by cryptographic mechanisms
       applied to the content of the original EDIFACT structures. The
       results of these mechanisms form the body of the AUTACK
       message, supplemented by relevant data such as references of
       the cryptographic methods used, the reference numbers for the
       EDIFACT structures and the date and time of the original
       structures.
       
       The AUTACK message shall use the standard security header and
       trailer groups.
       
       The AUTACK message can apply to one or more messages, packages
       or groups from one or more interchanges, or to one or more
       interchanges.
       
       1.3.1 Use of AUTACK for the authentication function
       
       An AUTACK message used as an authentication message shall be
       sent by the originator of one or more  other EDIFACT
       structures, or by a party having authority to act on behalf of
       the originator. Its purpose is to facilitate the security
       services defined in Part 5 of ISO 9735, i.e. authenticity,
       integrity, and non-repudiation of origin of its associated
       EDIFACT structures.
       
       An AUTACK authentication message can be implemented in two
       ways.  The first method conveys the hashed values of the
       referenced EDIFACT structures secured by the AUTACK itself; the
       second uses the AUTACK only to convey digital signatures of the
       referenced EDIFACT structures.
       
       1.3.1.1 Authentication using hash values of the referenced
       EDIFACT structures
       
       The secured EDIFACT structure shall be referenced in an
       occurrence of the USX (security references) segment. For each
       USX there shall be at least one corresponding USY (security on
       references) segment which contains the security result, for
       example the hash value, of the security function performed on
       the referenced EDIFACT structure.
       Details about the security function performed shall be
       contained in the AUTACK security header group. The USY and USH
       segments for the referenced EDIFACT structure shall be linked
       using security reference number data elements in both segments.
       
       As a final step, all the information conveyed in the AUTACK
       shall be secured using at least one pair of security header and
       security trailer groups.
       
       Note:
       AUTACK uses the USX segment to reference one or more messages,
       packages or groups in one or more interchanges, or to reference
       an entire interchange. For each USX segment a corresponding USY
       segment contains the result of the hashing, authentication or
       non-repudiation method applied to the referenced EDIFACT
       structure.
       
       1.3.1.2 Authentication using digital signatures of the
       referenced EDIFACT structures
       
       The secured EDIFACT structure shall be referenced in an
       occurrence of the USX (security references) segment. For each
       USX at least one corresponding USY (security on references)
       segment, which contains the digital signature of the referenced
       EDIFACT structure, shall be present. Details about the security
       function performed shall be contained in the AUTACK security
       header group. Because a single referenced EDIFACT structure may
       be secured more than once, the related USY and security header
       group shall be linked using security reference number data
       elements in both segments.
       
       If the digital signature of the referenced EDIFACT structure is
       contained in AUTACK (rather than just a hash value), the AUTACK
       does not itself require to be secured.
       
       1.3.2 The use of AUTACK for the acknowledgement function
       
       An AUTACK message used as an acknowledgement message shall be
       sent by the recipient of one or more previously received
       secured EDIFACT structures, or by a party having authority to
       act on behalf of the recipient. Its purpose is to facilitate
       confirmation of receipt, validation of integrity of content,
       validation of completeness and/or non-repudiation of receipt of
       its associated EDIFACT structures.
       
       The acknowledgement function shall be applied only to secured
       EDIFACT structures. The secured EDIFACT structure shall be
       referenced in an occurrence of the USX (security references)
       segment. For each USX there shall be at least one corresponding
       USY (security on references) segment which contains either the
       hash value or the digital signature of the referenced EDIFACT
       structure. The USY shall be linked to a security header group
       of the referenced EDIFACT structure, or of an AUTACK message
       securing it, by using security reference number data element.
       The corresponding security header related to the referenced
       EDIFACT structure contains the details of the security function
       performed on the referenced EDIFACT structure by the sender of
       the original message.
       
       As a final step in generation of the acknowledgement message,
       all the information conveyed in the AUTACK shall be secured
       using at least one pair of security header and security trailer
       groups.
       
       AUTACK may also be used for non-acknowledgement in case of
       problems with the verification of the security results.
       
       Note :
       Secure acknowledgement is only meaningful for secured EDIFACT
       structures. Securing EDIFACT structures  is accomplished by the
       use of either integrated security segments (see Part 5 of ISO
       9735) or AUTACK authentication.
       To prevent endless loops, an AUTACK used for the
       acknowledgement function shall not require its recipient to
       send back an AUTACK acknowledgement message.

2.     REFERENCES

       See UNTDID, Part 4, Chapter 2.6 UN/ECE UNSM - General
       Introduction, Section 1.

3.     TERMS AND DEFINITIONS

3.1    Standard terms and definitions

       See UNTDID, Part 4, Chapter 2.6 UN/ECE UNSM - General
       Introduction, Section 2.

4.     MESSAGE DEFINITION

4.1    Data Segment Clarification

       This section should be read in conjunction with the Branching
       Diagram and Segment Table which indicate mandatory, conditional
       and repeating requirements.

0010   UNH, Message header
       A service segment starting and uniquely identifying a message.
       The message type code for the secure authentication and
       acknowledgement message is AUTACK.
       The data element message type sub-function identification shall
       be used to indicate the usage of the AUTACK function as either
       authentication, acknowledgement or refusal of acknowledgement.
       
       Note: messages conforming to this document must contain the
       following data in segment UNH, composite S009:
       
       Data element  0065 AUTACK
                     0052 4
                     0054 1
                     0051 UN


0020   Segment group 1:  USH-USA-SG2
       A group of segments identifying the security service and
       security mechanisms applied and containing the data necessary
       to carry out the validation calculations (as defined in Part 5
       of ISO 9735).
       This segment group shall specify the security service and
       algorithm(s) applied to the AUTACK message or applied to the
       referenced EDIFACT structure.
       Each security header group shall be linked to a security
       trailer group, and some may be linked additionally to USY
       segments.

0030      USH, Security header
          A segment specifying a security service applied to the
          message/package in which the segment is included, or to the
          referenced EDIFACT structure (as defined in Part 5 of ISO
          9735).
          The security service data element shall specify the security
          function applied to the AUTACK message or the referenced
          EDIFACT structure:
          -  the security services: message origin authentication and
          non-repudiation of origin shall only be used for the AUTACK
          message itself.
          -  the security services: referenced EDIFACT structure
          integrity, referenced EDIFACT structure origin
          authentication and referenced EDIFACT structure
          non-repudiation of origin shall only be used by the sender
          to secure the AUTACK referenced EDIFACT structures.
          -  the security services: receipt authentication and
          non-repudiation of receipt shall only be used by the
          receiver of secured EDIFACT structures to secure the
          acknowledgement.
          
          The scope of security application of the security service
          shall be specified, as defined in Part 5 of ISO 9735. In an
          AUTACK message, there are four possible scopes of security
          application:
          -  the first two scopes are as defined in Part 5 of ISO 9735
          section 5.
          -  the third scope includes the whole EDIFACT structure, in
          which the scope of the security application is from the
          first character of the referenced message, package, group or
          interchange (namely a "U") to the last character of the
          message, package, group or interchange, inclusive.
          -  the fourth scope is user defined, in which scope the
          security application is defined in an agreement between
          sender and receiver.

0040      USA, Security algorithm
          A segment identifying a security algorithm, the technical
          usage made of it, and containing the technical parameters
          required (as defined in Part 5 of ISO 9735).


0050      Segment group 2:  USC-USA-USR
          A group of segments containing the data necessary to
          validate the security methods applied to the
          message/package, when asymmetric algorithms are used (as
          defined in Part 5 of ISO 9735).

0060         USC, Certificate
             A segment containing the credentials of the certificate
             owner and identifying the certification authority which
             has generated the certificate (as defined in Part 5 of
             ISO 9735).

0070         USA, Security algorithm
             A segment identifying a security algorithm, the technical
             usage made of it, and containing the technical parameters
             required (as defined in Part 5 of ISO 9735).

0080         USR, Security result
             A segment containing the result of the security functions
             applied to the certificate by the certification authority
             (as defined in Part 5 of ISO 9735).

0090   USB, Secured data identification
       This segment shall contain identification of the interchange
       sender and interchange recipient, a security related timestamp
       of the AUTACK and it shall specify whether a secure
       acknowledgement from the AUTACK message recipient is required
       or not. If one is required, the message sender will expect an
       AUTACK acknowledgement message to be sent back by the message
       recipient.
       The interchange sender and interchange recipient in USB shall
       refer to the sender and the recipient of the interchange in
       which the AUTACK is present, in order to secure this
       information.


0100   Segment group 3:  USX-USY
       This segment group shall be used to identify a party in the
       security process and to give security information on the
       referenced EDIFACT structure.

0110      USX, Security references
          This segment shall contain references to the party involved
          in the security process.
          The composite data element security date and time may
          contain the original generation date and time of the
          referenced EDIFACT structure.
          If data element 0020 is present and none of: 0048, 0062 and
          0800 are present, the whole interchange is referenced.
          If data elements 0020 and 0048 are present and none of: 0062
          and 0800 are present, the group is referenced.

0120      USY, Security on references
          A segment containing a link to a security header group and
          the result of the security services applied to the
          referenced EDIFACT structure as specified in this linked
          security header group.
          When the referenced EDIFACT structures are secured by the
          same security service, with the same related security
          parameters many USY segments may be linked to the same
          security header group. In this case the link value between
          the security header group and the related USYs shall be the
          same.
          When AUTACK is used for the acknowledgement function the
          corresponding security header group shall be either one of
          the referenced EDIFACT structure or of an AUTACK message
          that is used to provide the referenced EDIFACT structure
          with the authentication function.
          In a USY segment the value of data element 0534 shall be
          identical to the value in 0534 in the corresponding USH
          segment of either:
          -  the current AUTACK, if the authentication function is
          used (security services: referenced EDIFACT structure origin
          authenticity, referenced EDIFACT structure integrity or
          referenced EDIFACT structure non-repudiation of origin)
          -  the referenced EDIFACT structure itself, or an AUTACK
          message providing the referenced EDIFACT structure with the
          authentication function, if the acknowledgement function is
          used (security services: non-repudiation of receipt or
          receipt authentication)


0130   Segment group 4:  UST-USR
       A group of segments containing a link with security header
       segment group and the result of the security functions applied
       to the message/package (as defined in Part 5 of ISO 9735).
       USR segment may be omitted if the security trailer group is
       linked to a security header group related to a referenced
       EDIFACT structure. In this case the corresponding results of
       the security function shall be found in the USY segments which
       are linked to the relevant security header group.

0140      UST, Security trailer
          A segment establishing a link between security header and
          security trailer segment group and stating the number of
          security segments contained in these groups (as defined in
          Part 5 of ISO 9735).

0150      USR, Security result
          A segment containing the result of the security functions
          applied to the message/package as specified in the linked
          security header group (as defined in Part 5 of ISO 9735).
          The security result in this segment shall be applied to the
          AUTACK message itself.

0160   UNT, Message trailer
       A service segment ending a message, giving the total number of
       segments and the control reference number of the message.

4.2    Data segment index (Alphabetical sequence by tag)

          UNH Message header
          UNT Message trailer
          USA Security algorithm
          USB Secured data identification
          USC Certificate
          USH Security header
          USR Security result
          UST Security trailer
          USX Security references
          USY Security on references

4.3    Message structure

4.3.1  Segment table

Pos    Tag Name                                      S   R             Notes

0010   UNH Message header                            M   1             

0020       ÄÄÄÄÄ Segment group 1  ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ M   99ÄÄÄÄÄÄÄÄÄÄ¿ 
0030   USH Security header                           M   1           ³ 
0040   USA Security algorithm                        C   3           ³ 
                                                                     ³
0050       ÄÄÄÄÄ Segment group 2  ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ C   2ÄÄÄÄÄÄÄÄÄÄ¿³ 
0060   USC Certificate                               M   1          ³³ 
0070   USA Security algorithm                        C   3          ³³ 
0080   USR Security result                           C   1ÄÄÄÄÄÄÄÄÄÄÁÙ
0090   USB Secured data identification               M   1             

0100       ÄÄÄÄÄ Segment group 3  ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ M   9999ÄÄÄÄÄÄÄÄ¿ 
0110   USX Security references                       M   1           ³ 
0120   USY Security on references                    M   9ÄÄÄÄÄÄÄÄÄÄÄÙ

0130       ÄÄÄÄÄ Segment group 4  ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ M   99ÄÄÄÄÄÄÄÄÄÄ¿ 
0140   UST Security trailer                          M   1           ³ 
0150   USR Security result                           C   1ÄÄÄÄÄÄÄÄÄÄÄÙ
0160   UNT Message trailer                           M   1             
