Java Card Technology Ch 02 Smart card Basics

Java Card Technology Ch 02: Smart card Basics Instructors: Fu-Chiung Cheng (鄭福炯) Associate Professor Computer Science & Engineering Tatung University

Smart card n n Smart cards u are often, called chip cards, or integrated circuit(IC) cards. u are used for data transmission, storage, and processing u do not contain a power supply, a display or a keyboard (Need a CAD) The physical appearance and properties of a smart card are defined in ISO 7816, part 1 (see Fig 2. 1)

Divided into two card type memory cards & microprocessor cards contact cards & contactless cards

Memory cards n n n hold up 1 k to 4 k of data used for prepaid cards for public phones or other goods and services that are sold against prepayment does not have a cpu so it has limited functions and cannot be reprogramming also cannot be reused after the value in the card is spent can be counterfeited relatively easily Low cost (simple technology)

Microprocessor cards n n contain a processor u offer greatly increased security and multifunctional capability data are never directly available to the external applications Microprocessor controls data handling and memory access according to passwords, encryptions very flexible so it can be optimized for one application or can integrate several different applications

Contact cards must be inserted in a card acceptance device n communicate with the outside world by using serial communication interface n

Contactless cards n n n communicate with the outsize world through an antenna wound into the card power can be provided by an internal battery or can be collected by the antenna transmit data to a card acceptance device through electromagnetic fields

Contactless cards n n Advantages: u No contacts to become worm from excessive use u Cards do no need to be carefully inserted into a CAD u Cards do not have to be a standard thickness to fit in a CAD slot Disadvantages: u Expensive u Transmitted data may be intercepted

Smart card hardware n Smart card contact points: (see Fig 2. 2 on P. 15) u Vcc: supply power. u RST: sending the signal to reset the microprocessor (it is called a warm reset and a cold reset is done by switching the power supply off and on again) u CLK: t Smart cards do not posses internal clock t CLK point supplies the external clock signal from which the internal clock is derived

Smart card hardware n Smart card contact points: (see Fig 2. 2 on P. 15) u GND: t is used as a reference voltage; t its value is considered to be zero volts u Vpp: optional, only used in older cards. (for EEPROM) u I/O: transfer data and commands between the smart card and the outside world in half-duplex mode. (half duplex means that commands or data can be transmitted in only one direction at any particular time) u RFU: reserved for future use.

Smart card central Processing unit n CPU in most current card chips is an 8 -bit micro-controller, u u u n usually using the Motorola 6805 or Intel 8051 instruction set. Low end: up to 5 MHz High end: up to 40 MHz (5 MHz x 2, 4, 8) Newer smart card chips u u u have a 16 -bit or 32 bit micro-controller and use reduced instruction set (RISC) architecture 16 -bit or 32 -bit smart cards will likely become more common.

Smart card Coprocessors n n n Smart card chips for security applications have built-in crytographic coprocessor The crytographic coprocessor is a special IC for expediting calculations u Modular arithmetic u Large integer operations u ex RSA algorithm Affects cost of the chips

Smart Card Memory System n ROM, RAM, EEPROM are the most widely used memories.

ROM (read-only memory) is used for storing the fixed program of the card (e. g. operating system, permanent data) n no power is needed to hold data in this kind of memory but also can't be written to after the card is manufactured n can be accessed an unlimited number of times n

EEPROM (electrical erasable programmable read-only memory) n n n can preserve data content when power is turned off equivalent of the hard disk on a PC reading from EEPROM is as fast as reading from RAM, but writing to EEPROM is 1000 times slower than writing to RAM reliably accept at least 100, 000 write cycles retain data for 10 years.

RAM (random access memory) is non-persistent memory n is used as temporary working space for storing and modifying data. n the information content is not preserved when power is removed. n can be accessed an unlimited number of times n

flash memory n n a kind of persistent mutable memory (like EEPROM) more efficient in power and space than EEPROM can be read bit by bit but can be updated only as a block is typically used for storing additional programs or large chunks of data that are updated as wholes.

Smart Card Communication Model the communication pathway between the card and the host is half-duplexed; (that is, the data can either be sent from the host to the card or from the card to the host but not both at the same time. ) n smart card speak to other computer by using their own data packets-called APDUs (application protocol data units) n an APDU contains either a command or a response message u See Fig 2. 3 page 18 n

Command APDU structure Mandatory header n Format of a Command APDU (see Table 2. 1) u CLA (class of instruction): identify a category of command response APDUs. u INS (instruction code): specify the instruction of the command. u P 1 and P 2 (parameters 1 and 2): used to provide further qualification to the instruction.

Command APDU structure Optional body n Format of a Command APDU (see Table 2. 1) u Lc: specify the length of the data field u data field: contains data that are sent to the card for executing the instruction specified in the APDU header u Le: specify the number of bytes expected by the host in the card's response

Response APDU structure Optional body n Format of Response APDU (see Table 2. 2) u Contain data field whose length is determined by the Le field in the corresponding command APDU

Response APDU structure Mandatory Trailer n Format of Response APDU (see Table 2. 2) u SW 1 & SW 2: together called the status word, denoting the processing state in the card after executing the command APDU. t For example: status word 0 x 9000 means that a command was executed successfully and completely

Command response APDU cases n There are 4 cases (see Fig 2. 4 in pp 20) u Case 1: host (command only) <==> smart card(Status word) u Case 2: host (command only) <==> smart card(data+Status word) u Case 3: host (command + data) <==> smart card(Status word) u Case 4: host (command + data) <==> smart card(data + Status word)

TPDU n n n APDUs are transmitted by the next-level protocol (i. e. transport protocol), defined by ISO 7816 -3. The data structures exchanged by a host and a card using transport protocol are called Transmission Protocol Data Units (TPDUs). Two transport protocols in primary use u T=0 protocol: byte oriented u T=1 protocol: block oriented

Answer To Reset (ATR) n n Immediately after a smart card is powered up, it sends out an answer to reset (ATR) message to the host ATR message contains the parameters required by the card for establishing a data communication pathway. u u u n Transmission parameters t Transport protocol supported (T=0 or T=1) Data transmission rate Card hardware parameters t Chip serial number and mask version number ATR is up to 33 bytes

Smart Card Operating Systems n n Smart card operating systems (SCOS) have little resemblance to desktop OS. SCOS supports a collection of instructions on which user applications can be built. ISO 7816 -4 standardizes a wide range of instructions in the format of APDUs. Most SMOS supports File Systems

Smart Card File System n n Smart card file system defined in ISO 7816 -4 can have a hierarchical file system structure (see Fig 2. 5 in pp 21) ISO 7816 -4 file system supports three types of files: u master file (MF) u dedicated file (DF) and u elementary file (EF)

Smart Card File System n n n master file (MF) u the root of the file system. u can contain DF & EF u There is only one MF in a smart card dedicated file (DF) u is a smart card directory file that holds other DF & EF u a MF is a special type of DF elementary file (EF) u is a data file; can't contain other files.

Smart Card Systems Smart card systems are distributed systems that consist of two parts: u Host system: residing in the computer connected to the reader u Card system: inside a smart card n Most smart card software, including system software and user application software, runs on host side n

Smart Card Systems n System software on host system u recognizes a specific smart card and handles communication between the user and the card u provides supports to the smart card’s t Card management t Security t Key management

Smart Card Systems n User applications on host systems implement functions that work with a specific card u A simple user application: handle a set of APDUs exchanged with the card u ATM application: provide user authentication, transaction processing, and a friendly user interface for easy access.

Smart Card Systems n n User applications on host systems implement functions that work with a specific card u A simple user application: handle a set of APDUs exchanged with the card u ATM application: provide user authentication, transaction processing, and a friendly user interface for easy access. Host software is usually written in high-level languages such as Java, C, and C++

Smart Card Systems n n Card software is the software that run on the smart card itself Card software also includes u System software t u OS and utilities that control memory management, handle I/O communication with the host, ensure data integrity and security, support ISO file system and provide system utilities to the card applications User application software: t Data and functions

Smart Card Systems n n Card software can be implemented either in assembly language of the card microprocessor or in a high-level programming language that can be interpreted by the microprocessor Smart card systems involve co-operations between providers of the card OS, venders of card terminals, application developers (both card side and host side) and card issuers These parties are often not from the same companies Java card technology provides a ubiquitous platform in which card-side applications can be written in java and can run on any smart card that supports the Java Card runtime environment

Smart card standards and specifications ISO 7816 Standards n GSM(Global System for Mobile Communications) defined by u ETSI (European Telecommunication Standards Institute) n EMV (Europay, Master. Card and Visa) n OP (Open Platform) n OCF (Open. Card Framework) n