The one-card trick. Multi-application smart card E-commerce prototypes
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T has been exploring the brenefits of multi- application smart cards, i.e. processor cards which hold more than one application as well as data on the card. BT believes that market
trends indicate that electronic commerce will be a key arena for the use of smart cards.
The means to sign documents and authenticate yourself to remote parties to a transaction are vital to the widespread uptake of electronic commerce. Digital IDS based on public key cryptography will become the standard mechanism for achieving the required levels of secyrity. Since the use of multi-application smart cards substantially reduces the cost of developing and deploying smart card applications, the use of such cards as part of public key infrastructure (PKI) is very effective.
In addition, BT wished to examine the value of smart cards (storing digital IDS) as a secure and flexible identity
Consult Hyperion has designed and built prototypes for BT which show the use of a Multos multi-application smart card for storing a digital ID and then demonstrating various E-commerce business applications (secure E-mail, ticketing, Web site log on etc.) via a variety of devices and networks. In addition, dynamic loading and deletion of card applications after card issue has been demonstrated. This article describes the prototypes.
token that will provide access to a whole spectrum of services via a range of network terminals and devices, not just PCs.
BT asked Consult Hyperion to design and build portable prototypes: a laptop PC and a smart phone. The same smart cards work with both access devices without modification: the one-card trick. The prototypes commissioned demonstrate the following:
storing a digital ID on the smart card which is secure and portable using this digital ID on a smart card to: -gain access to secure Web sites -access E-commerce services such as Internet
storing data on the same smart card such as tele- phone numbers, E-mail addresses, or value tokens (e.g. tickets).
COMPUTING & CONTROL ENGINEERING JOURNAL JUNE 1999 121
GUassmq @Iff mGPauooyms term meaning
BT asked Hyperion to include Multos card application download and deletion across open networks. Building on digital ID on a smart card, BT chose to demonstrate
ADC ALC ALU BITC BT CA DES
LCD MEL MIME
MULTOS PC PCMCIA
PIN PKI PKC , PSTN RC2
(Multos) application delete certificate (Multos) application load certificate (Multos) application load unit bump in the cord British Telecom certificate authority Data Encryption Standard, a popular symmetric-key encryption method developed in 1975 and standardised by ANSI in 1981 electrically erasable programmable read only memory, a special type of PROM that can be erased by exposing it to an electrical charge; like other types of PROM, EEPROM retains its contents even when the power is turned off General Information Systems Ltd., Cambridge, UK interactive voice response, a talking computer designed to give information without a live operator; IVR systems can interact with a database of information from a mainframe computer; callers communicate with the system by using an ordinary touch tone telephone liquid crystal display Multos executable language multipurpose Internet mail extensions-the standard is universally used by Web servers to identify the files they are sending to Web clients, in thik way new file formats can be accommodated simply by updating the browsers list of pairs of MIME types and appropriate software for handling each type multiple application operating system personal computer the PCMCIA (Personal Computer Memory Card International Association) is an industry group organised to promote standards for a credit card-size memory or U0 device that would fit into a personal computer personal identification number public key infrastructure public key certificate public switched telephone network RC2 is a variable key-size block cipher designed by Ron Rivest for RSA Data Security; RC stands for Rons Code or Rivests Cipher; it is faster than DES and is designed as a drop-in replacement for DES secure sockets layer, a program layer created by Netscape for managing the security of message transmissions in a network; Netscapes SSL uses the public-and-private key encryption system from RSA, which also includes the use of a digital certificate
- the following services:
0 secure E-mail 0 secure E-ticketing 0 secure E-banking using a smart phone with a built-in
smart card reader.
A value-added service was also requested whereby card holders can store their favourite E-mail addresses and telephone numbers on the smart card.
~ M ~ ~ ~ - 3 l ~ ~ u ~ G Z l ~ ~ @ I ~ SooOZlm QXlUdS There are a number of multiple-application smart
cards emerging onto the market (Multos, JavaCard, Windows Card). BT expects that in the future these cards will all work together and that the card holders will be able to access services using any of the various card types.
At the time these prototypes were developed, Multos smart cards were chosen because they were the most advanced and provided a number of attractive features:
0 Security: The cards are tamper resistant and there are firewalls between the applications loaded on the card which prevent them from affecting each other.
0 Multi-application: By allowing more than a single application on the card, the business case for the card can be improved. In this prototype, the three applications are: security; E-friends and family; and E-ticketing. However, other card applications in the future may include: medical records; credit; debit; building access; GSM loyalty; library card.
0 Secure load/delete: The infrastructure for loading and deleting applications on Multos cards is well thought out, flexible and secure (see below). This means that users will be able to decide what applications they would like on their cards after they have been issued. Multos cards are therefore adaptable to future needs. Through the load and delete certificate mechanism, the issuer can control which applications the card holder is allowed to load or delete.
0 Powerful functionality: Multos cards have a number of powerful primitives resident which allow application developers to develop applications more easily which perform complicated operations on the Multos card, e.g. public key cryptography.
Multos card application load and deletion Card application load and deletion in the field after
card issue is one of the most attractive features of Multos cards. If the issuer allows it, the card holder may delete resident applications on their card and download new applications over open networks such as the Internet or DCThT \
* 122 COMPUTING & CONTROL ENGINEERING JOURNAL JUNE 1999
RT CARDS In order to load an application to the users Multos card, digital ID is PIN protected so that only the card holder
he must have the correct application load certificate can use it. The PIN may be up to 8 digits long. Non-digits (ALC) together with the application load unit (ALU). The are not allowed so that the PIN may be entered at a issuer may allow the card owner to obtain these files over terminal which only has a numeric key pad (e.g. a smart the Internet and they may be encrypted for added phone). security. The ALU is essentially the application code and The longer the cryptographic keys, the stronger the data. The ALC is a certificate which determines which cryptography generated by the keys. The key length is cards the application may be loaded onto. restricted by the browser in use since that is where the
If there is room on the users Multos card for the keys are generated. At the time of building the prototype, application, it may be loaded using appropriate software the strongest keys allowed by the version of Netscape which breaks up the ALU and ALC Communicator exported from the
USA were 512 bits long. However, the security MEL application is
into appropriate chunks and fires them at the card in the correct order.
Deleting applications from a o@rjjJ@~@gp@ Qpfi@kD8 capable of operating with longer Multos card is a similar process. The keys if reassembled with a constant correct application delete certificate changed. The effect would be to (ADC) is required for the card and increase the application data size application. The issuer may allow and so a new ALU would be
required also. A further restriction was that the Multos (v3.2) cards
the card holder to download this over the Internet. Deleting an application from a Multos card used here were limited to a key causes the application and its data length of 576 bits (Multos 4 cards to be lost permanently and the emerging at the time of writing will
allow 1024-bit keys). Once the digital certificate is
reserved space on the card becomes free for subsequent applications to be loaded. ~ h ~ @ a g h @[ff∾@n~ loaded (e.g. from BT Trustwise)
In this way, the Multos card onto the card, it resides inside the may be used as a lifestyle card. @@Vi@@@ security application. The Applications reside on the card as certificates are standard X.509 long as the user wants them and (with the card issuers permission) the users may delete applications and load When presented with the correct PIN, the security new ones as their requirements change.
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Prototyping Hyperion designed two prototypes for BT to meet the
requirements. The first is based on a laptop PC with Internet connection. The second uses a smart phone with PSTN connection to the outside world. The same smart card and applications on the card are/used with both prototypes. This is the one-card trick: the smart card is portable and secure and may be used to enable access to services through different access devices.
Whats on the cards? Three applications were developed to run on Multos
cards. On the 8 k cards available at the time of this work (which actually have only approximately 6 kbyte of EEPROM available for application code and data), there was not enough EEPROM to fit all three applications at the same time. However, dynamic application load an$ deletion allows the card holders to modify which applications reside on their smart card, so they are not prevented from using any services. Also, at the time of writing, the first 16 k Multos cards are emerging. (i) Security: The first MEL application holds a digital ID (a ceAificate and an asymmetric cryptography key pair) and enables them to be used for security purposes. The
0 On request, deliver the digital certificate held on the card (which contains the card holders public key). Allow the private key to be used on the card for signing, authentication and decryption of small items such as session secret keys, but will never reveal the private key. Generate a hash digest of the certificate on the card and sign it with the private key. This allows this application to operate in an environment where hashes cannot be generated off the card, e.g. when using a smart phone. If the application is used in conjunction
\ with a Web browser or other appropriate software, then the certificate hash may be generated off the card.
(ig Egriends and family: This application holds favourite names, telephone numbers and E-mail addresses. Up to ten records may be stored on a card. The application is merely a container which stores data and retrieves the same data when requested. Any textual data may be stored.
(i$ E-ticketing: This application stores electronic tickets. The tickets are-stored as journey legs, each signed by
COMPUTING & CONTROL ENGINEERING JOURNAL JUNE 1999 . 123
Fig. 1 PCDnternet functional diagram
the ticket issuer so as to prevent fraud. If a criminal intercepted an E-ticket on its way to the card and stored it to their hard disc, they may change the date and replay the data to store it to the card. However, the ticket would not be valid since the signature would not match the ticket body.
PCLnternet pro to type 6) Overview: As shown in Fig. 1, this prototype consists of:
0 the users laptop PC (with appropriate software loaded), a smart card reader and a Multos card (we used 8 k Multos 3.2 cards)
- 0 the Hyperion Web server 0 the BTTrustwise Web server (which issues digital
0 the Internet to connect the above together. IDS) 2 1-
69 Using the PC/Internetprototype: The typical sequence of actions which the user goes through once the prototype is installed on their PC is: ,
0 Load the security application on to the Multos card from the Hyperion Web server over the Internet.
0 Get a digital ID over the Internet using their Web browser and the BT Trustwise Web server and store it on their Multos card (inside the security application).
Now the user is in the position to be able to send and receive secure E-mails (see below) using their digital ID on their Multos card. 0 Sign terms and conditions over thelnternet using their
digital ID on their Multos card in order to be allowed to
load the E-friends and family application onto their Multos.
Now they can edit and store their favourite E-mail addresses and phone numbers on their Multos card (inside the E-friends and family application).
0 Delete the E-friends and family application to make room on the card for loading the E-ticketing applica- tion.
0 Access the Hyperion Web server to purchase electronic tickets by signing the transaction. Tickets are stored on the card (in the E-ticketing application).
Each of these stages outlined above is described in more detail below:
(iii) Curd application loud and deletion: As described earlier, when the user wishes to load or delete an application form their card, they need the permission of the issuer. In this demonstration, the applications which may be loaded or deleted are restricted to those which are available through the Hyperion demonstration Web site.
The loading of some card applications is restricted to holders of a valid BT Trustwise certificate. In order to be able to load the restricted applications, the user must first establish an SSL connection to the Web site using their digital ID on their smart card.
By pointing their browser at the Hyperion Web site, users may click on links which enable them to download the appropriate files required for application load (ALU and ALC) or delete (ADC). When the files arrive over the Internet, the browser checks the MIME type and auto- matically starts up the helper (see Fig. 2). h
- 124 COMPUTING & CONTROL ENGINEERING JOURNAL JUNE 1999
SMART CARDS The user is able to check
which applications are on the card by clicking the &rectory button. By clicking the Load or Delete buttons, the action is started. The scrolling window displays progress reports to the user.
(iv) Getting a digital ID from BT Trustwise onto a smart card: BT is currently offering free trial digital...