?? 051-053.html
字號:
<!-- Edit EirGrabber 3.01 -->
<HTML>
<HEAD>
<TITLE>Smart Card Developer's Kit:Some Basic Standards for Smart Cards</TITLE>
<CENTER>
<TABLE BORDER>
<TR>
<TD><A HREF="049-051.html">Previous</A></TD>
<TD><A HREF="../ewtoc.html">Table of Contents</A></TD>
<TD><A HREF="053-056.html">Next</A></TD>
</TR>
</TABLE>
</CENTER>
<P><BR></P>
<P>The interface characters are used as a selection method for the protocol used for subsequent higher-level communication between the reader and the card. Two such protocols are defined by ISO 7816-3—the T=0 protocol and the T=1 protocol. T=0 is an asynchronous protocol, meaning there is no strict timing connection between one command sent from the reader to the card and the next command sent from the reader to the card. When the card receives a command from the reader, it performs the requested operations and sends back to the reader a response relative to that command. The reader is then free to send the next command to the card whenever it needs to. The T=1 protocol is an asynchronous block transmission protocol. This means that in one transmission packet from the reader to the card, one to several commands are sent. The card responds to this (these) commands, at which point the reader can send another command or block of commands. Designations for additional protocols are defined as indicated in Table 3.6.
</P>
<TABLE WIDTH="100%"><CAPTION ALIGN=LEFT><B>Table 3.6.</B> Protocol designations.
<TR>
<TH WIDTH="25%" ALIGN="LEFT">Designation
<TH WIDTH="75%" ALIGN="LEFT">Definition
<TR>
<TD COLSPAN="2"><HR>
<TR>
<TD>T=0
<TD>Asynchronous (single) command/response protocol
<TR>
<TD>T=1
<TD>Asynchronous (multiple) command/response protocol
<TR>
<TD>T=2
<TD>Reserved for future full-duplex protocol
<TR>
<TD>T=3
<TD>Reserved for future full-duplex protocol
<TR>
<TD>T=4
<TD>Reserved for enhanced asynchronous protocol
<TR>
<TD>T=5
<TD>Reserved for future use
<TR>
<TD>T=6
<TD>Reserved for future use
<TR>
<TD>T=7
<TD>Reserved for future use
<TR>
<TD>T=8
<TD>Reserved for future use
<TR>
<TD>T=9
<TD>Reserved for future use
<TR>
<TD>T=10
<TD>Reserved for future use
<TR>
<TD>T=11
<TD>Reserved for future use
<TR>
<TD>T=12
<TD>Reserved for future use
<TR>
<TD>T=13
<TD>Reserved for future use
<TR>
<TD>T=14
<TD>Reserved for vendor-defined protocol
<TR>
<TD>T=15
<TD>Reserved for future extension
<TR>
<TD COLSPAN="2"><HR>
</TABLE>
<P>The ATR sequence that initializes the physical communication channel between the reader and the card allows a number of characteristics of the channel to be defined or manipulated. The ISO/IEC 7816-3 standard defines a more elaborate adjunct to the ATR sequence called the <I>Protocol Type Selection</I> (PTS) facility. Actually, the PTS can be thought of as an extension of the ATR. Through the PTS the reader side of the channel and the card side of the channel can negotiate to an optimum set of characteristics for the channel. For most current smart card systems, there is a strong correlation between the reader-side development and the card development. Consequently, the optimum communication characteristics are almost always derived through the ATR sequence without performing a PTS sequence. Therefore, we will not delve into the details of the PTS. However, in the future, with an expanding marketplace for smart cards encouraging more disconnected development of readers, terminals, and cards, the need to go through a PTS sequence on card initialization may significantly increase.</P>
<H4 ALIGN="LEFT"><A NAME="Heading8"></A><FONT COLOR="#000077">Other Smart Card Standards and Specifications</FONT></H4>
<P>ISO 7816 is unquestionably the most widely known and followed general-purpose smart card standard, but it is by no means the only one. There are standards for the use of smart cards in specific applications such as health, transportation, banking, electronic commerce, and identity. And there are standards for new kinds of smart cards such as proximity and contactless smart cards. Since a smart card is always part of a larger information technology, it is subject to a wide range of information-processing standards such as character sets, country encodings, monetary representations, and cryptography. Finally, since many smart card applications intersect a number of governmental concerns such as monetary systems, national identity, and benefit eligibility, there are national and regional smart card standards in addition to international standards.
</P>
<P>Due to the deliberate pace of international standards efforts, there are also a growing number of smart card specifications issued by organizations such as governmental laboratories, professional societies, trade associations, academic institutions and private firms not associated with standards bodies. These specifications have no force other than the force of the marketplace of products and ideas, but they do serve the useful role of stimulating discussion and consensus, which can be fed into official standards efforts. As smart cards are embraced within other technologies such as cellular telephones, watches, automobiles, and Internet browsers, we can expect that these technologies and their application domains will prompt rules and regulations about the nature of the smart card component. For the near term as smart card usage explodes, it will probably be as much the marketplace as the international standards process that will say how smart cards are supposed to be.</P><P><BR></P>
<CENTER>
<TABLE BORDER>
<TR>
<TD><A HREF="049-051.html">Previous</A></TD>
<TD><A HREF="../ewtoc.html">Table of Contents</A></TD>
<TD><A HREF="053-056.html">Next</A></TD>
</TR>
</TABLE>
</CENTER>
</BODY></HTML>
?? 快捷鍵說明
復(fù)制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -