Chip card security

[Teacher]

Security of microprocessor cards

There is an undeniable interest in microprocessor cards, despite the unequal level of their penetration into the markets of different countries. It provides an overview
of the security features for smart cards and provides an assessment of the security level.
Describes multipurpose cards (containing more than one application) and how
to manage those applications. It ends with an overview of the main standards
for multipurpose cards and the EMV specification (according to the first letters of the names of the
specification developers: Europay, MasterCard, Visa).

1. Classification and fields of use of microprocessor
cards
For the first time cards with integrated circuits (IC) were patented in the 70s in the USA,
Japan and France, and their full-scale commercial development began in Japan
in the 70s, in France in the 80s. There is now a trend of
widespread replacement of magnetic stripe cards with microprocessor cards, but in
e-commerce applications that are demanding in terms of memory, computing
performance and security.

Cards are of the following types:
Cards with bar codes.
Magnetic strip cards. These cards have
limited memory and cannot be programmed; as a consequence, they
cannot be used in applications where decision-making is necessary and there are
increased security requirements.
Integrated circuit cards:
- memory cards. They use a low-performance chip that allows you to store data and even provide
minimal protection. The performance of such cards is focused on
making prepaid payments (for example, telephone cards);
- hard logic cards (wired-logic cards). Such cards are used in applications
where minimal control of access to encrypted TV channels is required.
The cost of such cards is about US $ 1;
- microprocessor cards or smart cards. They are
programmable devices capable of performing complex calculations. Despite
thin (0.76 mm), the card contains a miniature computer, including an
operating system, memory and microprocessor. Such cards can support
advanced encryption techniques to authenticate parties, guarantee
data integrity and confidentiality. Unlike cards with a magnetic stripe,
payment authorization can be done offline.
IC cards can be used in three categories of commercial relationships:
B2B, B2C and face-to-face. The technical development of such cards is the result of the
merger of several technologies - microelectronics, software for transactions and
cryptographic methods. The price of microprocessor cards remains relatively high
and ranges from $ 5 to $ 20; there are
several compatible operating systems and programming languages on the market .
The first area of application of microprocessor cards is closed systems,
proprietary developments of firms. An example is calling cards that are only recognizable by the network of
one operator; cards for vending machines (parking machines,
public transport turnstiles , etc.). Today, smart cards can be
classified according to the following criteria:
Card usage time (there are disposable or “rechargeable” cards),
Intellect cards, which range from simple memory to gesture usage.
coy logic and programmable microprocessors.
The need for direct contact of the reader and the method of providing energy
(there are contact and contactless cards). Contact cards can transfer data at
speeds up to 9.6 Kb / s, contactless - up to 106 Kb / s.
Electromagnetic induction can be used as a power source for contactless cards , which makes them attractive for rail and trucking companies to pay tolls.
Characteristics of the card application. Distinguish between cards with one application and cards
with multiple applications - multipurpose cards.
Calling cards are usually disposable contact cards with one application,
their cost is about $ 0.50. The total number of telephone units
corresponds to the number of memory locations. When used, the cells are sequentially cleaned
. The amount of memory varies from 8 to 256 KB, but can reach hundreds of megabits.
Multipurpose cards can offer personalized services such as
badges, IDs, medical records, grade books, e-
wallets, and so on. Having multiple applications on a single card requires isolating the
memory areas used by each application. If access to the card depends on a PIN, communication
with each application can be controlled using a second set of secret
keys held by the application provider and customer.
Today microprocessor cards can be:

Bank cards.
Prepaid cards. If the values stored in the card are
fiduciary money, the card is an electronic wallet. A ***** operator
can only provide electronic tokens for any special service.
and Cards containing portable electronic documents (medical
records, grade books, etc.). Such maps are used by some European
universities. Examples of the use of such cards:
- SmameVitale in France and Versicherten-Karte in Germany - a way of
accessing an information system for collecting and storing administrative information;
- Hemacard in Belgium for people at risk - pregnant
women with cancer and other serious illnesses.
Access control of the cardholder to anywhere or to something can be carried out
physically (access to businesses, hotels, etc.) or logically (access to
software, secret databases, etc.). In this case, the card acts as a portable
calculator that uses dynamic passwords to authorize
user access. This type of application is more typical for security systems
than for electronic payments.
Adaptation of IC cards for use in computers. Several
attempts to make a microprocessor card standard equipment of a personal
computer. The main initiatives in this area are the creation of the OpenCard
Framework (OCF), PC SC and Java Card specifications . An experimental
UNIX file system for smart cards has also been created .
OCF is a product of the OpenCard consortium and is a common
programming interface for smart card readers and card applications. It is based on
Java technology and is incompatible with C and C ++ languages. OCF supports multi-
slot readers to access more than one card at a time; this feature is useful in
financial and medical applications where the presence of a master card is required (master
- cards) to allow access to a second card, which may belong to the customer
or patient.
PC / SC is an abbreviated version of the"

Interoperability Specification for Integrated Circuit Cards and Personal Computer Systems", created by a working group of
representatives of leading manufacturers of microprocessor cards and personal
computers: Bull CP8, GemPlus, Schlumberger, Hewlett-Packard, IBM, Sun and Microsoft.
The specification is written for Windows and supports many
programming languages . Microsoft has developed its own cryptographic library -
CryptoAPI used by Windows to access cryptographic functions and
certificates stored in smart cards. CryptoAPI also enables
secure messaging and certificate management. This library is
subject to US export restrictions on cryptographic software.
The Java Card specification defines a subset of the Java language for
use in microprocessor cards. Using Java allows developers to
create smart card applications that are independent of the microprocessor and
operating system. Application portability is achieved by using a
Java virtual machine on top of an operating system.

1.1. Contact pad cards
In cards with a contact pad (integrated circuit cards with contacts), the clock
frequency varies from 3.5 to 5 MHz, the supply voltage is from 3 to 5 V. In the
previous generation chips, the programmable memory worked from a power supply of 5 - 15 V and
even 21 V. Progress microelectronics made an additional power
supply unnecessary, which increased resistance to attacks through changes in supply voltage. Moreover, it became possible to use the released contact for two-way
(duplex) data transmission.
The IC card has 8 contacts, resistant to mechanical damage, corrosion,
contamination and damage by chemical reagents. Contact arrangement
is determined by the standard, however, manufacturers may define the
purpose of the contacts in different ways.
Readers are usually equipped with a mechanism for automatically capturing the card
when it is inserted into the slot. This increases the reliability of reading and "vandal resistance"
(albeit at the expense of increasing the complexity of the device and the cost of operation).
Contacts of the card with IC

Microprocessor cards have two types of memory:
• read-only memory (ROM);
• random access memory (RAM).
The ROM contains a mask of a card with a length of several kilobits, which contains the
operating system. RAM stores intermediate calculation results and
variables. Static RAM, unlike DRAM, does not require
periodic content refresh to prevent data loss.

The contents of the ROM are independent of the power supply. ROM can be of the following types:
• programmable read-only memory (PROM);
• erasable programmable read only memory (EPROM).

The contents of the EPROM can only be erased by exposure to ultraviolet radiation.
This type of memory is commonly used in disposable cards. EPROM is used in
programmable cards to store encryption keys and other variable values. To write a
value to an EPROM cell, two clock cycles are required: the first is to erase the information, the second is to
records. The use of new types of memory, such as flash memory or ferrite memory
(FeRAM), can reduce write time and power consumption.
Currently, the cards use 8-bit processors, 16KB ROM. RAM
256 or 512 bytes and PISA 3-8 Kbytes. From a functional point of view, the memory of the microprocessor
card is organized according to the hierarchy of zones:
o The production area is the part of the memory recorded before personalization.
Contains the batch number of the chip backing, the name of the backing manufacturer and its serial
number, the serial number of the card and the ID of the card supplier.
o Secret area. It contains confidential information of the cardholder
-PIN-code, secret cryptographic keys and personal data files.
o A transactional or work area that stores temporary
confidential information about a transaction (for example, the amount of a transaction). This
storage area is available for all multipurpose card applications.
o Access control area, in which the microprocessor keeps a log of attempts to
access a secret or transactional area (if this area is protected). Using such a zone allows you to block the card after several unsuccessful access attempts
(usually no more than three).
o Free zone, which contains non-confidential information
such as the names of the cardholder and issuer, as well as the expiration date of the card. This zone has
access all multipurpose card applications.
The operating system currently used depends on the card manufacturer. One of the most commonly used masks in single app maps is the
M4 mask. Among the makers of masks for multipurpose cards, there are two main
competitors - the Maosco consortium, led by Mastercard and including Hitachi,
Gemplus and Siemens. They offer the Multos operating system developed by
Mondex International. Visa International is spearheading the JavaSoft consortium backed by Sun
Microsystems, Schlumberger, Motorola and Gemplus to offer its
Java technology-based card specification.

2. Security of microprocessor cards
The microprocessor card protects sensitive data stored in the memory of
the card, as well as secure access to services. The purpose of the security process
is to:
• protect against counterfeiting at all stages of production,
• protect against theft of applications and ROM-based security software,
• protect the information stored in the card,
• detect and prevent attempts to unlawful use of the card.
Each phase of the card's life cycle implies the implementation of a sufficient level of
security to move to the next level.

There are seven stages in the issuance, personalization and distribution of microprocessor
cards.
1. Development of the chip.
2. Development of embedded software (firmware).
3. Creation of silicon substrates.
4. Placement of the chip and firmware on the substrate, packaging of the chip and final
testing.
5. Pre-personalization with the addition of programs depending on the purpose of the
card and testing them.
6. Personalization of the chip by placing in the memory of the card the names of the issuer and the
owner and application applications.
7. Issue of a smart card in the form of a plastic card with embossed printing, logo printing; card distribution.

The following participants are required for the production of the card:
• an integrated circuit (IC) and embedded software developer;
• IS manufacturer and security software developer;
• certification center;
• application developer;
• manufacturer of the actual carrier of the chip - a plastic card (design, relief printing, logo printing, etc.);
• card issuer - the organization responsible for the content of the card and
delivery to the end user.
The required
level of security must be ensured at all stages of card production and transportation . At the development stage, it is necessary to ensure the safety of design
documentation for IS, software, pre-personalization procedures and the safety of the
production environment. The security policy is to identify all possible types of
threats and develop appropriate protective measures during production and transportation.
Control is established over the production environment - materials and
production tools , good and defective copies. Potential threats include disclosure of
product requirements, modification or theft of materials or finished goods, modification of
software (including IC firmware and operating system).
IC manufacturers start by manufacturing a silicon wafer that houses
multiple ICs. At this stage, each IC is tested for the operability of the
microprocessor. Working instances are locked using symmetric encryption with a silicon workshop key (factory key) 8 or 16 bits long; on the substrate is marked with the batch number and manufacturer's identifier. The fabrication key is calculated using the master key and using the diversification algorithm. This algorithm calculates the factory key based on the master key and
card number. This method allows the CA to authenticate all batches without
storing all the keys. At the final stage, the defective ICs are cut from the substrate, the substrate with the
working chips is sent to the card manufacturer.
During pre-personalization, the card supplier cuts individual chips from the substrate,
which are then pressed into the plastic card. On the back of the card there may be
the manufacturer's logo is placed. After that, the chip is tested, and if
the tests are successful, the supplier will unlock the chip using the factory key. It then
loads its operating system, prints the serial number on the card, and blocks direct
write to memory. From this point on, access to the memory is carried out through logical
addressing to protect the recorded data from alteration or unauthorized access.
Before delivery to the software supplier, the card is blocked again, this time in front of the
issuer's personalization (or transport) key.
At the personalization stage, the software provider transfers application files, personal
information of the owner (owner ID, PIN code and unlocking keys) to the card.
vania). The card is then delivered to the end user.
When using the card, depending on the commercial offer, the owner may
be given the opportunity to change some personal parameters (for example, the
PIN code).

The card can become invalid for several reasons:
o The card has expired. In the case of a card with one application, the
card expiration date is the same as the application expiration date . For a multipurpose card, the expiration date corresponds
to the expiration date of the master file. When the application expires, the
operating system blocks write and update operations; the read operation is not
blocked to allow subsequent analysis of the operations performed.
o All possible memory locations reserved for data are full.
If the correct PIN is entered, it is still possible to read only the contents
of the card memory. To maintain access to a service or service provided by the card, a new card is required.
o Fraudulent use or card theft. In this case, the issuing organization simultaneously blocks the PIN of the card and the unblocking key. Partial
blocking (eg blocking a particular PIN) only affects the application using
that PIN and can be removed by the application owner using the
appropriate unblocking key.

2.1. Physical security of the card when using it
The security architecture of cards used in financial transactions is standardized by
ISO 10102. The ANSI X9.17 / ISO 8732 standard governs
key management procedures . The plastic card contains elements intended for identification of the
issuer and personalization (establishing a connection between the owner and the card). The location of
these elements may vary depending on the country in which the map is used.

On the front side of the card there are:
• contacts of the card chip;
• logo of the card issuer, financial institution and payment system;
• embossed printing of the serial number of the card, the name of the holder and the expiration date of the card;
• hologram - to increase the level of protection against counterfeiting, the location of the hologram is the same for all countries.

There is a place for the holder's signature on the back of the card. There may also be an
address for returning the card if found; for North America - a list of associated
payment systems. Elements for identification, PIN-code verification, expiration
date and codes describing the card's functionality are located on the magnetic stripe on the back of the card.
The card number consists of 10-19 characters, divided into groups of four characters. The first digit in the first group defines the payment system (4 for VISA, 5 for MasterCard, etc.), the
next digits define the country, the representative of the payment system in this country and the card number. The last four digits are the verification code ("Luen's key").
In general, smart cards are equipped with attack-resistant chips — when a physical attack is detected, the chip blocks withdrawal operations. The dielectric layer
is the passive protection of the chip from dirt, dust and radiation. When this layer is removed, the chip can react to light, changes in temperature, frequency, and voltage.
To prevent selective erasure of memory cells or the placement of sequential
words in independent memory cells, physical protection of memory cells is provided.
To deactivate special test ICs used at the arbitrariness stage, fuses are provided, which are burned out before the cards are distributed.

2.2. Logical security of the card when using it
At the stage of use, logical access control is carried out at three levels.
The first level is user authentication by entering a PIN-code, the second is to define a set of privileges for the card, and the third is to establish a secure logical connection channel
between the card (via the terminal) and the remote server. In face-to-face-commerce card authentication can be carried dealer:
o using a variety of physical means (identity card, signature
oposredstvom authorization server request;
opri means of PIN-code, which is digitally signed for procedures
withdrawals or payments.
Microprocessor cards can use complex authentication procedures.
In order to avoid transmission of the PIN-code or session keys in unencrypted form,
symmetric encryption algorithms (usually before DES, now AES) are used to check the integrity of the message and authenticate the sender , including in the mode of
generating the MAC message authentication code.
In online authorization systems, the process consists of two stages:
o mutual authentication of the owner and the card;
o mutual authentication of carp and terminal.
Note that many systems use their own protocols, the EMV Consortium
(EuroPay, MasterCard, Visa) has created its own specification for financial
transactions. GSM mobile telephony also uses a standardized procedure
remote authentication.
In the case of offline authorization (for example, when paying in the South African
electricity billing system ), the card contains a credit charged for the use of electricity. In
this symmetrical encryption algorithm is used.
Mutual authentication of the owner and the card.
Mutual authentication of the cardholder is as follows.
After placing the card in the slot, the reader asks the card to generate a random number, usually 64 bits long.
The owner enters the PIN-code on the reader's keypad.
The reader encrypts this number according to the algorithm specified by the payment system,
using the PIN-code as a key. The reader sends this number back to the card.
The card performs the same operations using the PIN code stored in its memory, and then
compares the result and the value received from the reader.
The result of the comparison determines whether mutual authentication was successful.
Mutual authentication of card and terminal.
If the previous phase is successful, then mutual authentication of the
card and the terminal begins .
The terminal generates a random number and sends it to the card.
The card encrypts this number with a secret key, depending on the selected type of service.
The encryption algorithm is determined by the payment system. The encrypted number is
sent back to the terminal.
The terminal performs similar calculations and compares the result with the value,
received from the card.
The result of the comparison determines whether mutual authentication was successful.
Audit management. Most audit management procedures require the chip to
record certain events and transaction details in a special audit file that is
later sent to the audit control center. Most smart cards have a
failed access counter . If the number of unsuccessful attempts has not reached a certain threshold, the counter is reset to zero on the first successful access attempt. If the threshold value is
exceeded, access to the card or a specific file is blocked. Some cards
allow the user to independently set the number of unsuccessful attempts for
card blocking, in others this value is preset and varies from 3 to 7 attempts.

2.3. Examples of implementation of safety procedures during
use of the card
Memory card reader for Minitel. The LECAMC (Lecteur de Cartes a Memoire) card reader was created to provide secure smart card transactions
for Minitel).
EMV card. EMV cards are designed for face-to-face commerce.
EMV specifications assume the use of a public key authentication algorithm.
Card authentication requires the exchange of four messages,
symmetric encryption and MAC are used to identify the owner. To form a MAC
the secret session key is used, which is also held by the bank.

An EMV session consists of the following stages.
1. Application selection.
2. Authentication of application data.
3. Determine general session restrictions due to incompatibility between map and server
versions, differences due to geographic location, or restrictions
imposed by the service provider.
4. Owner authentication.
5. Risk management (request for authorization, audit management, etc.).
6. If necessary, an online request for authorization is sent to the authorization server.
7. Updating data in the card memory.

 

[Teacher]

Table 13.2.
Symbols Used Designation
ARD
ARQC
CA
CERT_C
CERTJ
IAD
PAN
RCP
Name
Comment
Date, Time, Card
ID Terminal ID, Nonce 1
Authorization Request Data
Authorization
Cryptogram Certification Authority
Identifier Microprocessor Card Public Key Certificate Issued by the issuing bank (Certificate of Card) The issuer's public key certificate (Certificate o Issued by the certification center

Authentication data of the issuer (Issuer Authentication The number of the special card account (Private Accoun
The client's account linked to the card
Reference control parameter Contains the parameters of the
transaction user (online / offline)
The closed
key of the card is used for calculation
Amount, currency, date, time, PAN, terminal identifier popse2
SIGN_C (ARD) signature ARD, calculated card
TC
TD
certificate transaction
(transaction Certificate)
The data transaction (transaction data)

upon receipt of the command returns the card terminal READ_RECORD
CA certification authority identifier, certificates of public keys of the issuer and the
microprocessor card, account number associated with the card, and PIN-code, which
is stored in the memory of the card. The card's response determines the authorization method: online - with the
involvement of the bank or offline - using only the terminal. Both certificates are
required for the terminal to authenticate the card's public key in the
CERT_C message . To perform challenge-response
authentication A user authentication strategy that checks that he or she
responds correctly to an unpredictable system request. The terminal issues the INTERN AL_AUTHENTICATE
command with the ARD data required for authentication. This data
includes the date and time of the transaction, card ID, card-linked account number
(PAN), terminal ID, and nonce1 timestamp to prevent
replay attacks . In response, the card transmits a signature of this data, generated
using its private signing key.
The terminal then issues the VERIFY command to verify the user's PIN. The
cardholder enters the PIN, the card returns the verification result (successful / unsuccessful). The response of the
card is not encrypted, as EMV cards are designed for face-to-face commerce.
The GENERATE_AC command contains the RCP parameter and the TD transaction data. RCP determines the
method of conducting a transaction - online (with a survey of the bank's authorizer) or offline,
If the transaction is carried out online, the card generates an encrypted authorization
request (ARQC), which the terminal sends to the bank. ARQC contains the MAC of the
TO transaction data , which is calculated by the card using the session key (held
by the acquiring bank), which in turn is calculated based on the shared master key.
Thus, the bank can verify the authenticity of the request and determine its
origin. If the verification is successful, the bank returns a message with a response to the
authorization request, which contains the issuer authentication data (IAD) and may
contain command scripts for the card. The terminal forms the second command
GENERATE_AC, which contains IAD and a script. The card responds with a message containing
the TS transaction certificate and its MAC to confirm the authenticity of the transaction. Later, the
bank will check the authenticity of the vehicle and the sender. Note that the terminal does not check the answer,
since it does not have a session key available in the memory of the card and the bank.
In the case of offline authorization, the card response contains a vehicle that confirms or
rejects the transaction. The vehicle can be later sent to the bank to verify the authenticity of the vehicle
and the sender.

3. Attacks on Smart Cards
The literature describes many types of physical and logical attacks. The attacks
were carried out by amateurs, technical experts and
reverse engineering organizations. There are three main categories of attacks:
• logical (without penetration under the shell of the card);
• physical (with destruction of the protective coating);
• attacks that exploit errors and shortcomings of the map developers.

3.1. Logical attacks
Logical attacks are divided into active and passive. Active attacks alter
environmental conditions in order to cause the chip to malfunction and compromise
hidden information. EPROM write operations can be affected by changing the ambient
temperature, briefly raising the supply voltage, or increasing
the chip's clock frequency in order to cause the microcontroller to malfunction.
It has been determined that encryption keys and security software stored in the EPROM memory are
is vulnerable to this type of attack, otherwise known as a glitch attack,
because it can prevent the execution of test routines. For example: The
operation of the random number generator can be disrupted when
the power supply is reduced so that it starts to produce a single value.
For PIC16C84 microcontrollers, the security bit can be cleared and the
memory erased when the supply voltage is increased.
For DS5000 controllers from Dallas Semiconductor, a momentary
drop in supply voltage can disable the protection mechanism without erasing
the memory contents.
Some protected processors are so sensitive to changes in environment that register many false alarms.
On the contrary, passive attacks are aimed at "eavesdropping" and observing the
reactions of the card in order to detect surges of voltage or radiation. This is possible
due to the fact that each instruction has its own specific feature by which
it can be distinguished from others (for example, branch commands or operations
using a coprocessor). Passive methods include
differential power analysis (DPA), based on the fact that
power consumption depends on the number of bits involved in the operation.

3.2. Physical Attacks
A physical attack begins with removing a chip from a card. Plastic is cut off the card
until the epoxy appears, under which the chip is hidden. The resin
is washed off with concentrated nitric acid and washed in acetone until then. until the
entire silicon substrate is available. After freeing the chip,
it becomes possible to investigate the behavior of its various components and by
brute force to calculate the cryptographic keys. The
state of the microcontroller can be read using a laser probe or a focused ion beam. The cost of
this type of attack is relatively high and usually meaningless to casual hackers and
hobbyists.

3.3. Attacks Exploiting Developers' Identified Errors
As noted earlier, smart card protocols use symmetric
encryption. Although many card manufacturers claim to use
high-quality algorithms in cards , research has revealed some flaws in
implementations, for example, of the DES algorithm:
• In the Cryptofkx chip from Schlumberger, the DES algorithm is available only by
special order;
in a Multiflex chip from the same manufacturer, DES is used only
for the internal authentication command and only returns 48 bits for
use as an
encryption key;
• in a multifunctional card (MFC) from IBM, which can contain
several applications, it is not possible to set the key directly;
• in the Gemplus GPK chip, the key size is limited to 40 bits to match
cryptographic legislation of France (which was in force at the time of its development).
• In some cases, the internal test circuits of the chip, which must be
deactivated before the card is shipped to the market, are subsequently reactivated.

4. Multipurpose Smart Cards
These cards allow you to use multiple applications on a single card, sharing
resources without compromising security. The creation of standardized interfaces
helps to facilitate the development of such applications, since the application can be used
on cards from different vendors. ISO 7816-4 is the most preferred standard
not only when using open specifications such as EMV and Java
Card, but also for the companies' own developments. This section begins with a description of the file
system in accordance with the ISO 7816-4 standard.

4.1. ISO 7816-4
File System The ISO 7816-4 file system supports two categories of files: dedicated
files (DF is the equivalent of a "folder" in the Windows file system) and
elementary files (EF). Each file has an identifier encoded in two
bytes in hexadecimal format.

File system structure ISO 7816-4
At the root of the tree is the master file (MF), it always has the identifier 3F 00.
The identifier of the first DF is 01 00, the last one is ZE 00. Thus, the card cannot
contain more than 62 dedicated files and one master file. Each DF is
application-specific and can contain one or more elementary files. Application selection is
carried out using the SELECT FILE command with an
application identifier (A \ D) as an argument, or indirectly using elementary
files D \ R (directory) or ATR (Answer to Reset) (these files will be discussed below ).
EF files contain data. Each EF is identified by its position in the
tree, in other words, the path to the master file. The EF identifier is also encoded in two
bytes and takes the form xx yy, where xx is the DF identifier to which EF belongs.
Thus, xx = 3F if the file belongs directly to the master file; woo -
sequential numbers for files in the same directory. Therefore, the number of files
in one directory cannot exceed 63.
Elementary files 2F 00 and 2F 01, located under the master file, will perform
special index functions. The first is called DIR, the second is ATR. In other words, the
DIR file contains elements to identify the application, and the ATR file
defines how the map accesses files and other objects.
The maximum number of elementary files in a card is 63 x 63 = 3969
files. In fact, this is an inflexible structure, it is not suitable for dynamic
situations where files can be added or removed when adding or removing
applications. In fact, the ISO 7816-4 standard does not allow the creation of new files, and
vendors are forced to develop their own commands to manage the files.
ISO 7816-4 distinguishes between two types of elementary files: internal and working.
The latter contain data for the exclusive use of external entities.
Internal EFs contain data that the card uses during operation. For example, for a
money application, these files can be:
• Key files for storing keys that will be used to
calculate the session key specified by the used payment protocol.
In banking transactions, applications that use e-wallets,
usually several keys are needed - one for each transaction (for certification,
for debit, for credit or for electronic signature). Each key
is placed in an individual file.
• Files of PIN codes that control access to application files.
Application files and access conditions are determined at the personalization stage and cannot
be changed.
• Wallet files. For each wallet, the file contains the maximum
value of its balance, the operation limit for one transaction, the current balance and a
backup of the previous balance in case of failure.
• Certificate files - if
public key cryptography is used.
• Working files of applications.

4.2. Swedish Electronic Identity Card
An example of the use of the file system just described is the
Electronic Identity card (EID) used in Sweden. This card complies with the Swedish SS 61 43 30 standard developed by SEIS (Secured
Electronic Information in Society). SEIS is a
Swedish non-profit organization of about 50 firms in the financial and
industrial sectors, the Swedish public administration sector, dedicated to the
introduction of new technologies. In this application, the master file contains the following
elementary files:
• EFpan file defining the account number, embossed (in relief
printed) on the card.
• EFpin file defining the PIN-code common for all card applications, and
DIR-file (2F 00), which in accordance with the ISO 7816-4 specification contains the
identifier of the e-passport card.
• Dedicated application file with three elementary files:
1. application usage file (AUF) EFauf;
2. the private RSA key file EF;
3. EFCERT certificate file.

Logical organization of files and electronic ID card

4.3. Managing Applications in Multipurpose Cards
There are three different ways to manage applications, depending on the type of
communication between applications that coexist on the same card:
• the main application can control additional applications;
• several applications can be combined under the control of a
certification authority;
• all installed applications are independent.
The sub app is controlled by the main app. This situation
requires careful coordination between the providers of different applications for the correct
allocation of map resources. The current versions of operating systems for cards are not multitasking and
are close in their characteristics to the operating systems of computers of the 70s.
When distributing and organizing data files, supplementary applications
are treated as logical subsets of the main application.

The index file (DIR or ATR) that points to the dedicated add-on files
is defined once and for all during the card personalization phase. Information can
only be transferred between secondary and main applications. When accessing
the main application, access is automatically granted for additional
applications.
Consolidation of multiple applications managed by a certification authority. In this
case, applications use general data, such as personal information about the owner.
The separation of information is carried out under the supervision of a certification authority that controls the
master file. The CA is usually the card provider.
The CA assigns a unique identifier to each application and
stores it in an index file. This file points to a dedicated file for each
application. Any application has the right to read the contents of this file, the
write rights are regulated by the certification authority.
To get started, the application must first authenticate itself to the common
security module : when application A requests access to application B's data, the common
security module must authenticate. The security module then sends an
authentication request to application B to determine if application A has
access rights.
Multiple applications managed by a certification authority
Such a configuration should provide for special efficient mechanisms for the
exchange of digital identities - keys and certificates. An important initiative
in this area is the format defined in PKCS # 15, but there is still a
need to standardize many other aspects.
Independent applications on one card. There is no single
certification authority in this model . Application IDs are assigned in chronological
order in which they were added and are contained in an index file, which is usually accessed
using a public key algorithm.
Each application vendor develops applications according to
the map API specifications, then distributes the applications between
users directly or through intermediaries.
The Java Card architecture is based on this mechanism. Sharing
objects and resources securely between Java Card applications is still an open issue.

5. Standardization of microprocessor cards
Standardization of smart cards is necessary for two reasons. Firstly, the introduction of standards
leads to a decrease in production costs for the production of cards, and secondly, it
facilitates the interaction of applications through the use of consistent interfaces.
The standardization is quite developed with regard to the physical aspects of the card, the Logic
layer is still not sufficiently standardized, which prevents widespread adoption
financial applications. This section describes standards for contact
pad and contactless cards and EMV standards for multipurpose cards.

5.1. Standards for Contact Pad
Cards The ISO 7816 standard provides assurance that the card and
reader are physically compatible. The first version of the specification described the physical parameters of the card - dimensions,
pin arrangement, supply voltage, shape and length of electrical signals, and
protocols for interaction between the card and the terminal. As new commercial
smart card applications emerge, applications and
additions are developed to the core specification. Today the standard consists of six parts:
ISO 78I6-1. The oldest part that defines the physical characteristics of the card,
chip size, resistance to static discharges and electromagnetic radiation, the flexibility of the
plastic base and the location of the chip on the card.
SO 7816-2 describes the electrical signals (polarity, voltage, duration, etc.), the protocols for transferring data between the card and the terminal, and the reaction of the card when
the terminal is restarted. Currently, four protocols are defined:
- a half-duplex protocol designed for character-by-character data transmission (T = 0);
- half-duplex protocol for packet data transmission (T = 1);
- packet full-duplex protocol (T = 2) - rarely used;
- T = 14 means the use of a non-standard proprietary protocol
used to support applications developed before the introduction of the
standard. An example is the maps used in the healthcare sector in France and Germany.
The values T = 3 and T = 13 are reserved for future use,
ISO 78I6-4 defines the logical organization of the data stored in the card and the procedures for providing secure access to this data, namely:
- owner authentication using a password (PIN-code);
- authentication of an external entity using a secret key that
authenticates the terminal or bank;
- checking the integrity of data using a cryptogram (usually this is a code
message authentication - MAC);
- data encryption.

ISO 7816-4 commands fall into three categories: administrative commands,
security commands , and communication control commands. Most manufacturers prefer to
use commands from the standard, so most commercial cards use a
subset of the ISO 7816-4 standard. Additional proprietary commands
are used to facilitate file and data management.
ISO 7816-5 defines a procedure for registering applications to assign them a
worldwide application identifier AID;
ISO 7816-6 defines cross-industry map elements.
The EMV specifications are built on the ISO standards for multipurpose cards used
in financial transactions. ETSI has published standards for calling cards with non-
how many applications.

5.2. Standards for contactless cards
Contactless cards are powered by batteries or by
electromagnetic induction to avoid direct contact with the reader. Data exchange
with the reader is carried out using electromagnetic induction or
capacitive communication at a distance of 10-20 cm from the reader at a speed of up to 19.2 Kb / s. The
frequencies used are in the range reserved for industrial (less than 150
kHz) or medical (-6.78 MHz) applications. The ISO 10536 series of standards defines the
physical and mechanical aspects of contactless cards.
The advantage of contactless cards is the ability to reduce wear on the reader
teli and the cost of installation. The cards are designed for conditions where their carriers are moving at
low speeds; for example, in public transport, when paying for road
gates, etc. Data exchange protocols must correctly handle situations
when the reader has several cards at the same time.

5.3. EMV
EMV-3 specifications were published in 1996 and revised in 1998 by
EuroPay, MasterCard and VISA. The specifications define a
multi-application card architecture . Although the specifications are based on the ISO 7816 standard, the
main innovation of EMV is the use of object-oriented methodologies, which
makes it easier to integrate multiple applications into one card.
EMV specifications have been implemented by the International Air
Transport Association (IATA ) for
airline ticket payments , Berkeley Bank for its own bank cards, and others. As stated earlier, Java Card makes it easier to develop
EMV applications , the alternative is to use MultOS.
EMV specifications are designed for point-of-sale applications where the
POS is operated by the merchant's bank or the issuing bank. In this case, the
order belongs to face-to-face commerce, and the merchant and the bank interact via a
secure channel.

Considering that the order is carried out on a face-to-face basis and the goods are delivered
to the customer immediately, the protocol does not authenticate the seller, does not include a
description of the purchased item, or a guarantee of delivery of that item prior to debiting the
buyer's account . It is assumed that the physical presence of the card can be confirmed visually, the
protocol does not link the various parts of the transaction to confirm that
the same card was used throughout the entire transaction. Also, it is not possible to
unambiguously authenticate the terminal for the card; the terminal does not
unambiguously authorize any part of the transaction. Thus, if an order is made offline
(without involving a bank), the customer does not have formal proof of the
transaction.

Moreover, since it is not assumed that there is a secure communication channel between the
terminal and the card, there is no tool for protecting transmitted messages.
The terminal authenticates the card once and does not check the
calculations performed by it in the future . Therefore, in the case of offline authorization, the merchant cannot verify the
transaction data.In addition, since the bank and the merchant trust each other, the
merchant's terminal does not verify the data it receives from the bank, and the bank trusts the terminal to
deliver messages to the card.