WO2010003274A1

WO2010003274A1 - Portable electronic device managing xml data

Info

Publication number: WO2010003274A1
Application number: PCT/CN2008/001293
Authority: WO
Inventors: Xiang Zhou
Original assignee: Gemalto Sa
Priority date: 2008-07-09
Filing date: 2008-07-09
Publication date: 2010-01-14

Abstract

The invention is a portable electronic device intended to be connected to a host machine. The portable electronic device comprises a non volatile memory, a working memory, a communication interface, a microprocessor, means able to parse queries of XPath and XQuery type and means able to parse XML data.

Description

PORTABLE ELECTRONIC DEVICE MANAGING XML DATA

(Field of the invention)

The present invention relates to portable electronic devices which are intended to manage XML data. It relates particularly to portable electronic devices with limited memory and processor resources. In particular, the present invention applies to smart cards and memory cards having a microprocessor.

(Prior art)

The extensible Markup Language, also named XML, is a meta markup language for text documents. Data are included in XML documents as strings of text. The data are surrounded by text markups that describe the data. An XML basic unit of data with its markup is called an element. The XML specification is a standard defined by the World Wide Web Consortium (W3C) . The XML specification defines the exact syntax that the markup follows, how elements are delimited by tags, what a tag looks like, what names are acceptable for elements, where attributes are placed, and so forth. More in details, XML specification defines that an element is demarcated by a start tag, such as <tagname>, and an end tag, such as </tagname>. The information between the start tag and the end tag constitutes the content of the element. For example, <lastname>MyName</lastname> is an XML formatted for the name .

An element can be encapsulated into another element. An element can also be annotated with one or more attributes that contain metadata about the element and its content. For example, a record for an employee can be formatted as follow:

<lastname>Kokenoo</lastname> <firstname>Matt</firstname>

</employee>

Such a record constitute an element that comprises an attribute named "id" associated to a value "13579" that can identifies the record, and two element, one for the last name and the other one for the first name. For building a file with all employee, the record are written in text mode one after the other.

It is known to use SQL requests for accessing XML data stored in a smart card. For example a web application of a host machine may send SQL requests for retrieving data store on XML format in a smart card. A problem is to develop a powerful communication channel between a host machine and a portable electronic device comprising XML data. Another problem is to find an alternative solution to SQL mechanism.

(Summary of the Invention)

An object of the invention is to solve the above mentioned technical problems. The invention provides a solution for managing data in a full XML-oriented model .

The object of the present invention is a portable electronic device intended to be connected to a host machine. The portable electronic device comprises a non volatile memory, a working memory, a communication interface and a microprocessor. The portable electronic device comprises a first means capable of parsing queries of XPath and XQuery type. The portable electronic device may comprise a second means capable of parsing XML data.

Advantageously, the portable electronic device may comprise a third means capable of managing the storage of XML data. The queries of XPath and XQuery type may be sent by the host machine through a protocol of ISO-7816 type.

Alternatively, the queries of XPath and XQuery types may be sent by the host machine through a protocol of ISO-7816 type encapsulated in block protocol like USB, SD or MMC.

Alternatively, the queries of XPath and XQuery types may be sent by the host machine through a block protocol like USB, SD or MMC. Advantageously, first and second means may be event-driven parsers.

Advantageously, the portable electronic device may comprise a fourth means capable of receiving queries of

XPath and XQuery type sent by the host machine. The fourth means may be capable of receiving XML data sent by the host machine. The fourth means may be capable of delegating XPath and XQuery queries and XML data parsing to the first means or to the second means.

In a preferred embodiment, the fourth means may be an applet . Advantageously, the portable electronic device may be a smart card, a SD card or an enhanced USB token.

(Brief description of the drawings)

Other characteristics and advantages of the present invention will emerge more clearly from a reading of the following description of a number of preferred embodiments of the invention with reference to the corresponding accompanying drawings in which:

- Figure 1 depicts schematically an example of an embodiment of a portable electronic device of SIM card type according to the invention;

- Figure 2 depicts schematically an example of architecture of Java card operating system of a portable electronic device according to the invention; - Figure 3 depicts schematically an example of step sequence for managing XML data in a smart card according to the invention; and

- Figure 4 depicts schematically an example of architecture of software components dedicated to management of XML data in a portable electronic device according to the invention.

(Detailed description of the preferred embodiments) The invention may apply to any types of smart card or memory cards having a microprocessor. In particular, the invention may apply to SD ® cards, MMC cards, and enhanced USB tokens. A SD ® card is also named a Secure Digital ® card. A MMC card is also named a MultiMedia Card. An enhanced USB token may be defined as a flash USB token comprising a microprocessor.

An advantage of the invention is to provide a high level interface to a portable electronic device.

Figure 1 shows the architecture of a portable electronic device PED of SIM smart card type according to a first embodiment of the invention.

The portable electronic device PED comprises a microprocessor MP, a communication interface INT, a non volatile memory MEMl , and a working memory WM like a RAM. The communication interface INT is intended to be connected to a host machine HM. The connection may be carried out through a wireless or contact channel. In the example, the interface INT is capable to communicate with the host machine through a protocol according to the ISO-7816 standard. The host machine is intended to send queries of XPath and XQuery type to the device PED. The host machine may also send XML data intended to be stored in the device PED. In a preferred embodiment, the memory MEMl is a Flash memory. The memory MEMl contains an operating system OS, XML data XD and four means Ml, M2, M3 and M4. The first means Ml is capable of parsing queries of XPath and XQuery type. The second means M2 is capable of parsing queries of XML type. The third means M3 is capable of managing the storage of XML data. The fourth means M4 is capable of receiving queries of XPath and XQuery type sent by the host machine HM. The fourth means M4 is capable of receiving XML data sent by the host machine. The fourth means M4 is also capable of delegating query parsing to first, second and third means Ml, M2 and M3.

In the above described example the four means Ml, M2, M3 and M4 are shown as four distinct elements having each one a specific function. These four elements may be merged in one or several pieces of software.

In the above described example the operating system OS, the XML data XD and the four means Ml, M2, M3 and M4 are comprised in a unique memory MEMl. Alternatively, the portable electronic device may comprise several non volatile memories. The operating system OS, the XML data XD and the four means Ml, M2, M3 and M4 may be stored in any combination of non volatile memories.

Figure 2 shows the architecture of the operating system of a SIM Java card according to the invention.

A first layer comprises a Java Card Runtime Environment also named JCRE and a Java Card Virtual Machine also named JCVM. In this example, the first layer is based on Java Card technology, but the invention applies also to a first layer implemented in native language.

A second layer comprises a XML engine manager, a XML parser and a XPath/XQuery parser. The XPath/XQuery parser corresponds to the first means Ml of Figure 1, the XML parser corresponds to the second means M2 of Figure 1 and the XML engine manager corresponds to the third means M3 of Figure 1. Moreover the second layer comprises a file system able to manage data according to UICC requirements. The second layer may comprise additional other native extensions like security encryption and decryption engine, network protocol handler and processor.

In a preferred embodiment, the XML parser and XPath/XQuery parser are event-driven parsers. Such event-driven parsers may be based on the Simple API for XML mechanism, also called SAX. The SAX interface comprises a forward-only reader that moves across a stream of XML data and "pushes" events of interest (e.g., the occurrence of a start tag indicating the beginning of an element) to registered event handlers

(such as callback methods in an application) to parse the element content. SAX allows an application to parse

XML documents that are larger than the amount of available memory.

The XML engine manager is a manager wrapper for XML data storage, error and exception handling. XML data must be trimmed and serialized in order to be loaded and stored in the smart card. XML sequential data is sent to the card. Then predefined XML storage process is triggered on card side.

The XML engine manager performs the following three steps :

At a first step, the XML header is processed: The XML version and encoding are checked and recorded at this stage. In particular, the encoding, UCS-2 and other types of data encoding determine the XML data size and presentation. The Document Type Declaration, also named DTD, is checked.

At a second step, unnecessary characters are removed. This step allows optimizing data size for storage performance reasons. For example, the following characters may be removed: unnecessary space character between every two attribute elements in ^ΛΛ<" >" pair or space character between every node pair. Moreover for XML information storage on card the "\r\n" character on card is not necessary, only data are mandatory but not the presentation characters.

At a third step, a verification of the XML form is carried out. The verification step on card is necessary because the incoming XML sequential data may be not well-formed. XML syntax checking can be synchronized with the data storage.

A third layer comprises a XML/XPath/XQuery API, a,

UICC API, a SIM API and may comprise other APIs. All these Java APIs are intended to be published for third party application development. UICC stands for

Universal Integrated Circuit Card.

The storage of XML data may be done through predefined XML files in the UICC file system, like EF. In particular transparent binary files or record files under folders MF or ADF or DF can be used for XML data storage.

Alternatively, the storage may be performed through objects stored in the non volatile memory area MEMl. In particular, the available EEPROM/Flash area may be used with a compliant logical-physical address mapping.

Alternatively, the storage may be performed in FAT in big memory cards. The FAT file system may be used in big memory cards for XML data storage as well as large multimedia data.

The XML parser may be based on the SAX technology. The key point is that SAX is event-driven based which is relevant for smart card operating systems.

An advantage of the invention is to provide a lightweight solution for memory and microprocessor resources and may be applied for any huge XML files which do not need to construct the whole DOM (Document Object Model) tree of the XML document.

Figure 3 shows schematically an example of workflow for managing XML data in a smart card according to the invention. The XML parser may be implemented in order to comply with part or the whole of XPath 2.0 and XQuery 1.0 standards. Queries of XPath/XQuery type mainly aim at writing and retrieving XML elements set and data through expressions. The expressions work like a filter especially in event-driven XML parser. XPath/XQuery expression should be submitted at the beginning of the XML session. The XML parser parses the XML data and generates events for elements and characters. But for XPath/XQuery, only a subset of the events requires to be forwarded to the XML enabled applet. The elements and data which comply with the XPath/XQuery expression will be passed to the application. So the application only processes the relevant elements and data.

XPath/XQuery parser co-works with the XML parser and works as a filter, which forwards all the events complying with the XPath/XQuery expression.

An applet which utilizes the XML related API to share XML services is called an XML enabled Applet. At step 1, a XML enabled Applet submit an XPath/XQuery request. Then at step 2, the XPath/XQuery parser forwards the query request to the XML engine manager. At step 3, the XML engine manager registers the request to the XML parser and sets this request as an XML events filter. At step 4, the XML enabled Applet invokes a method to start XML parsing. At step 5, all the generated events are filtered by the XPath/XQuery parser and only the events that comply with the XPath/XQuery expression can trigger the event handling methods implemented by the XML enabled Applet. The triggering of the relevant event handling methods is then performed at step 6.

Figure 4 shows schematically an example of architecture of software elements dedicated to management of XML data in a portable electronic device according to the invention.

A XML delegate application is implemented as an applet with a specific identification data named AID. When this applet has been selected thanks to its AID, the XML data and XPath/XQuery queries may be sent to this applet. The XML delegate application is able to receive queries of XPath and XQuery type and XML data sent by the host machine HM. As shown in Figure 4, the

XML data and XPath and XQuery may be sent by the host machine through APDU according to ISO-7816 standard.

The XML delegate application corresponds to the fourth means M4 of Figure 1.

Alternatively the XML data and XPath and XQuery may be sent by the host machine through ISO-7816 APDU encapsulated in a data block protocol like USB, SD or

MMC for example. Alternatively the XML data and XPath and XQuery may be sent by the host machine directly through a data block protocol like USB, SD or MMC.

Moreover the XML delegate application is able to delegate queries parsing to XPath/XQuery parser and to XML parser. In addition, the XML delegate application is able to delegate storage of XML data to the XML engine manager.

In other words, the XML delegate application can be used as an interface between an off card application and XML oriented components embedded in the smart card.

Claims

1. A portable electronic device (PED) intended to be connected to a host machine (HM) , said portable electronic device (PED) comprising a non volatile memory (MEMl) , a working memory (WM) , a communication interface (INT) and a microprocessor (MP) , characterized in that said portable electronic device (PED) comprises first means (Ml) able to parse queries of XPath and XQuery types.

2. A portable electronic device (PED) according to claim 1, wherein said portable electronic device (PED) comprises second means (M2) able to parse XML data.

3. A portable electronic device (PED) according to one of claims 1 to 2, wherein said portable electronic device (PED) comprises third means (M3) able to manage XML data storing.

4. A portable electronic device (PED) according to one of claims 1 to 3, wherein said queries of XPath and XQuery types are sent by the host machine (HM) through a protocol of ISO-7816 type.

5. A portable electronic device (PED) according to one of claims 1 to 3, wherein said queries of XPath and XQuery type are sent by the host machine (HM) through a protocol of ISO-7816 type encapsulated in block protocol like USB, SD or MMC.

6. A portable electronic device (PED) according to one of claims 1 to 3, wherein said queries of XPath and XQuery types are sent by the host machine (HM) through a block protocol like USB, SD or MMC.

7. A portable electronic device (PED) according to one of claims 1 to 6, wherein said first and second means (Ml, M2) are event-driven parsers.

8. A portable electronic device (PED) according to one of claims 1 to 7, wherein said portable electronic device (PED) comprises fourth means (M4) able to receive queries of XPath and XQuery types sent by the host machine (HM) and XML data, and wherein said fourth means (M4) is able to delegate queries parsing and XML data parsing to said first means (Ml) or said second means (M2) .

9. A portable electronic device (PED) according to claim 8, wherein said fourth means (M4) is an applet.

10. A portable electronic device (PED) according to one of claims 1 to 9, wherein said portable electronic device (PED) is a smart card, a SD ® card or an enhanced USB token.