Trade Working Group February 2001
INTERNET-DRAFT Ko Fujimura
Masayuki Terada
Expires: August 2001 NTT
XML Voucher: Generic Voucher Language
<draft-ietf-trade-voucher-lang-00.txt>
Status of This Document
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
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Distribution of this document is unlimited. Please send comments to
the TRADE working group at <ietf-trade@lists.elistx.com>, which may
be joined by sending a message with subject "subscribe" to <ietf-
trade-request@lists.elistx.com>.
Discussions of the TRADE working group are archived at
http://www.elistx.com/archives/ietf-trade.
Abstract
This document specifies rules for defining voucher properties in
XML syntax. A voucher is a logical entity that represents a right
to claim goods or services. A voucher can be used to transfer a
wide-range of electronic-values, including coupons, tickets,
loyalty points, and gift certificates, which are often necessary to
process in the course of payment and/or delivery transactions.
K. Fujimura, M. Terada [Page 1]
INTERNET-DRAFT XML Voucher February 2001
Table of Contents
Status of this Memo ..............................................1
Abstract .........................................................1
1. Introduction ..................................................2
2. Processing Model ..............................................2
3. Trust Model ...................................................3
4. Component Structure ...........................................4
4.1 Voucher Component .........................................4
4.2 Promise Component .........................................4
5. Syntax Overview and Examples ..................................6
6. Semantics .....................................................7
7. DTD ...........................................................7
8. Security Considerations .......................................7
9. Acknowledgments ...............................................7
10. References ....................................................7
11. Author's Address ..............................................8
1. Introduction
This document, XML Voucher, specifies rules for defining voucher
properties in XML syntax. The motivation and background of the
specification is described in [GVT].
A voucher is a logical entity that represents a certain right and
logically managed by the Voucher Trading System (VTS). A voucher is
generated by the issuer, and traded among users, and finally is
collected by the collector using VTS.
This document defines syntax and semantics of the Voucher Component
that is used to define voucher meaning and processing rules in XML
syntax [XML]. In a Voucher Component, properties needed to allow
the voucher to be processed by VTS or other trading systems, e.g.,
wallet or merchant system, are described. VTS definitions and
models are also defined in [GVT].
Note: This document uses a "voucher" as an "instance of voucher"
whose meaning is defined by Voucher Component. In other words,
multiple vouchers can be issued and managed by the VTS using the
same Voucher Component.
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. Processing Model
There are several ways of implementing VTS and technologies are
K. Fujimura, M. Terada [Page 2]
INTERNET-DRAFT XML Voucher February 2001
continuously changing. For discount coupons or event tickets, for
example, the smart-card-based offline VTS is often preferred,
whereas for bonds or securities, the centralized online VTS is
preferred. It is impractical to define standard protocols for
issuing, transferring, or redeeming vouchers at this moment.
To provide implementation flexibility, this document assumes a
modular wallet architecture that allows multiple VTS to be added as
plug-ins. In the architecture, instead of specifying a standard
voucher transfer protocol, two specifications, i.e., Voucher
Component and VTS API specifications, are standardized (Figure 1).
Sender wallet/Issuing system Receiver wallet/Collecting system
+---------------------------+ +---------------------------+
| | | |
| | Voucher Component | |
| | (Specifies Issuer, Promise, Holder, and VTS Provider) | |
| |-------------------------------------------------------->| |
| | | | | |
| | Intention to receive and payment (option) | |
| |<- - - - - - - - - - - - - - - - - - - - - - - - - - - - | |
| | | | | |
| | Issue/transfer/ VTS | | VTS Register | |
| | redeem request plug-in | plug-in request | |
| |------------------>| | | |<------------------| |
| | (VTS API) |<- - - - - - - ->| (VTS API) | |
| | | VTS-specific | | |
| | | protocol if VTS | | |
| | | is distributed | | |
| | Event |<- - - - - - - ->| Event | |
| |<------------------| | | |------------------>| |
+---------------------------+ +---------------------------+
Figure 1. Wallet architecture with VTS plug-ins
After sender and receiver agree on what vouchers are to be traded
and which VTS is to be used, the issuing system or wallet system
requests the corresponding VTS plug-in to permit the issue,
transfer, or redeem transactions to be performed via the VTS
API. The VTS then rewrites the ownership of the vouchers using a
VTS-specific protocol. Finally, a completion event is sent to the
wallet systems or issuing/collecting systems.
3. Trust Model
A voucher is trusted if the issuer and VTS provider are trusted,
since the issuer is responsible for the contents of the voucher and
the VTS provider is responsible for preventing ownership from being
assigned to multiple users. This model enables trading partners to
verify the trust of the voucher regardless of the trust of the
partners.
K. Fujimura, M. Terada [Page 3]
INTERNET-DRAFT XML Voucher February 2001
The trust level required for issuer and VTS provider depends on the
type (or Promise) of the voucher. To provide the information needed
for the verification, the conditions of issuer and VTS provider are
specified in the Voucher Component.
In this case, however, if a malicious user could alter the Voucher
Component, a forged voucher, would be verified as valid. This
document, therefore, assumes that such alteration is impossible
during delivery of the Voucher Component; this is possible with
existing technologies, such as [XMLDSIG] or [TLS].
Note: The Voucher Component does not have to be sent from the
sender of the voucher. It can be directly delivered from the
trusted issuer or trusted third party using TLS or other secure
communication channel. Note also that a set of trusted Voucher
Components can be pre-downloaded before conducting a transaction.
4. Component Structure
4.1 Voucher Component
A Voucher Component provides VTS branding information, and basic
properties for representing a voucher, i.e., issuer, promise, and
holder. Implementation-specific properties are often required for
authenticating issuer and holder. These implementation-specific
properties of the VTS can be attached as child elements using
[XML-ns].
The Voucher Component contains Provider Component, Issuer
Component, Promise Component, and Holder Component as follows:
Provider Component
Provides properties to specify which VTS Provider (or VTS
plug-in) can be used for trading the voucher.
Issuer Component
Provides properties specifying the issuer of the vouchers. This
is optional and can be omitted if the issuer role is delegated to
the VTS Provider.
Promise Component
Provides properties used by the application system of VTS, e.g.,
wallet system, merchant system. The Promise Component is
transparent to the VTS and is described in Section 4.2.
Holder Component
Provides properties to specify the holder of the vouchers. This
is optional and can be omitted if the vouchers are
transferable. (Note: Even for transferable vouchers, this
K. Fujimura, M. Terada [Page 4]
INTERNET-DRAFT XML Voucher February 2001
component may be used by the VTS depending on the
implementation.)
4.2 Promise Component
The Promise Component provides common properties useful for
displaying and manipulating wallet systems. It includes monetary
property (value) of the voucher. These monetary properties are
needed to calculate the amount paid when the vouchers are redeemed
at Merchant site, etc.
The Promise Component contains Title Component, Description
Component, ValidPeriod Component, Redemption Component, Merchandise
Component, and Value Component as follows:
Title Component
Provides the title of the voucher. This is mainly for displaying
the list of entities stored in a wallet system.
Description Component
Provides a short description of the voucher. This is mainly for
displaying the entities stored in a wallet system.
ValidPeriod Component
Indicates voucher's validity period, start date and end date.
Redemption Component
Provides the number of vouchers to be redeemed for claiming the
merchandise or financial value specified in Merchandise Component
or Value Component. If "n" (>0) is specified, the merchandize can
be claimed in exchange with "n sheets of" vouchers. (Note:
Multiple vouchers for the same Voucher Component must exist in
this case.) If "0" is specified, the vouchers do not need to be
consumed. It can be used repeatedly regardless of the number of
times redeemed.
Merchandise Component
Provides domain-specific meaning of the voucher, e.g., reference
number of the merchandize or seat number for an event ticket,
which is needed to identify the merchandize rendered when the
voucher is redeemed. The properties of this component are left to
the other domain-specific specifications and out of scope of this
document. Domain-specific properties can be attached as child
elements using [XML-ns].
Value Component
Provides the value of the vouchers. There are two types of
K. Fujimura, M. Terada [Page 5]
INTERNET-DRAFT XML Voucher February 2001
values, i.e., fixed and ratio values. For a fixed value, the
currency and amount of the value is specified. For a ratio value,
the discount ratio of the price of the corresponding merchandize
is specified.
Using the above Components, monetary meaning for diverse types of
vouchers can be defined as shown in Table 1.
+---------------+----------+---------------+---------------------+
| |Number | | Value |
| Examples |needed for| Merchandise +-----+---------------+
| |redemption| |Ratio| Fixed |
| | | | |Amount Currency|
+---------------+----------+---------------+-----+------+--------+
|Gift certifiate| 1 |(Not specified)| | 25 | USD |
|Loyalty point | 20 |(Not specified)| | 200 | AUD |
|Member card | 0 |(Not specified)| 0.2| | |
|Coupon | 1 |Beef 500g | 0.3| | |
|Event ticket | 1 |Hall A, S ,K23 | 1.0| | |
|Exchange ticket| 1 |ISBN:0071355014| 1.0| | |
+---------------+----------+---------------+-----+------+--------+
Table 1. Examples of vouchers and their properties
5. Syntax Overview and Examples
This section provides an overview and examples of Voucher
Component. The formal syntax and semantics are found in Sections 6
and 7.
Voucher Components are represented by the <Voucher> element which
has the following structure (where "?" denotes zero or one
occurrence; "+" denotes one or more occurrences; and "*" denotes
zero or more occurrences):
<Voucher>
(Provider)
(Issuer)?
<Promise>
(Title)?
(Description)?
(ValidPeriod)?
(Redemption)?
(Value)?
(Merchandise)+
</Promise>
(Holder)?
</Voucher>
An example of a Voucher Component is described below. This is an
example of a five dollar discount coupon for specific merchandize,
a book with ISBN number 0071355014. The coupon is valid from April
K. Fujimura, M. Terada [Page 6]
INTERNET-DRAFT XML Voucher February 2001
1st in 2001 to March 31st in 2002. To claim this offer, one voucher
must be spent.
<?xml version="1.0"?>
<Voucher xmlns="http://www.ietf.org/rfc/rfcXXXX.txt"
xmlns:vts="http://www.example.com/vts.txt">
<Provider Name="Voucher Wallet 2001">
<vts:KeyInfo>...</vts:KeyInfo>
</Provider>
<Issuer Name="Alice Book Center, Ltd.">
<vts:KeyInfo>...</vts:KeyInfo>
</Issuer>
<Promise>
<Title>IOTP Book Coupon</Title>
<Description>$5 off IOTP Book</Description>
<ValidPeriod start="2001-04-01" end="2002-03-31"/>
<Redemption spend="1"/>
<Value currency="USD" amount="5"/>
<Merchandise xmlns="http://www.example.com/book.txt">
<BookID ISBN="0071355014"/>
</Merchandise>
</Promise>
</Voucher>
6. Semantics
(tbs)
7. DTD
(tbs)
8. Security Considerations
Security issues for delivering Voucher Components are discussed in
Section 3. Security is a major issue in implementing VTS. For XML
Voucher, however, the only requirements for achieving security are
to provide the parameters needed for establishing security.
9. Acknowledgement
(tbs)
10. References
[ECML] ECML Version 2, to appear.
[GVT] K. Fujimura, "Requirements for Generic Voucher Trading",
draft-ietf-trade-drt-requirements-02.txt, February 2001.
[IOTP] D. Burdett, "The Internet Open Trading Protocol", RFC2801,
K. Fujimura, M. Terada [Page 7]
INTERNET-DRAFT XML Voucher February 2001
April 2000.
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[TLS] T. Dierks, C. Allen, "The TLS Protocol Version 1.0", RFC2246,
January 1999.
[XML] "Extensible Mark Up Language (XML) 1.0 (Second Edition)", A
W3C Recommendation, <http://www.w3.org/TR/REC-xml>, October 2000.
[XMLDSIG] "XML-Signature Syntax and Processing",
draft-ietf-xmldsig- core-11.txt, in RFC Editor queue for
publication as Proposed Standard.
[XML-ns] "Namespaces in XML", A W3C Recommendation,
<http://www.w3.org/TR/REC-xml-names>, January 1999.
11. Authors Address
Ko Fujimura and Masayuki Terada
NTT Corporation
1-1 Hikari-no-oka, Yokosuka-shi, Kanagawa, 239-0847 JAPAN
Phone: +81-(0)468-59-3814
Fax: +81-(0)468-59-2241
Email: fujimura@isl.ntt.co.jp, terada@isl.ntt.co.jp
K. Fujimura, M. Terada [Page 8]
