How does the Smart Card Works?

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How does the Smart Card Works?

What is a Smart Card?

A smart card is a special type of card like device which contains an integrated circuit chip embedded on it. The IC chip can be a microprocessor with memory or just simple memory circuit. In simple layman’s words, a smart card is the card with which we can exchange the data, store it and manipulate data.

How does the Smart Card Works?

A smart card is connected to the host computer or controller via a card reader which gets information from the smart card and accordingly passes the information to the host computer or controller.

A basic Smart Card Working System

A Basic Smart Card Working System

What is a Smart Card Reader?

A smart card reader is a device to which the smart card is connected either directly or indirectly using RF communication. It interfaces with the PC or a microcontroller using USB port or RS232 serial ports. It can be a contact or contactless reader.

Smart Card Reader

Smart Card Reader

2 Types of Smart Card based on Connection to the Smart Card Reader

  • Contact Smart Card:  This type of smart card consists of electrical contacts which are used to connect to the card reader where the card is inserted. The electrical contacts are deployed on a conductive gold plated coating on the card surface.
A contact smart card with electrical connections

A Contact Smart Card with Electrical Connections

  • Contactless Smart Card: This type of smart card communicates with the reader without any physical contact. Rather it consists of an antenna with which it is used to communicate using Radio Frequency band with the antenna on the reader. It usually receives power from the reader via the electromagnetic signal.
A Contactless Smart Card

A Contactless Smart Card


2 Types of Smart Cards based on their Functionalities and Configuration

  • Memory Cards: These are cards which only consist of memory circuits. It can only store, read and write data to a particular location. The data cannot be processed or manipulated. It can be a straight memory card which is only used to store data or a protected memory card with a restricted access to the memory and which can be used to write data. It can also be a rechargeable or a disposable card which contains memory units which can be used only once.
A Memory Smart Card

A Memory Smart Card


  • Microprocessor Based Cards: These cards consist of microprocessor embedded onto the chip in addition to the memory blocks. It also consists of specific sections of files with each file associated with a particular function. The data in files and the memory allocation is managed via an operating system which can be a fixed operating system or dynamic operating system. It allows for data processing and manipulations and can be used for multifunctioning.
Microprocessor Based Smart Card

Microprocessor Based Smart Card


4 Steps to Construct a Smart Card

  • The first step involves designing. The designing involves specifying the chip for the memory size, clock speed, volatile memory types, type of operating system and specifying the application software, specifying the card type, size and functioning and additional features.
  • The second step involves chip fabrication. This involves mounting the silicon chip on an epoxy glass substrate with gold plated connectors, using a die. The silicon chip is bonded to the connectors using connecting wires (wire bonding technique) or using flip chip technology (using a solder). The chip on board substrate is then sealed using epoxy resin and glued to the card substrate. The card substrate can be PVC based plastic card or Polyester based card.
  • The third step involves loading the code to the memory using special commands.
  • The fourth step involves data loading into the PROM memory such that the data pertains to the single person.

Advantages of Smart Card:

  • Might be promptly reconfigured
  • Reusable
  • Secure transactions
  • Gives more security
  • More tough and dependable
  • Permit numerous provisions to be saved in one card

5 Areas of Smart Card Applications:

  • Telecommunications: The most prominent use of smart card technology is in the development of SIM card or Subscriber Identity Module. A SIM card provides unique identification to each subscriber and provides network access to each subscriber and manages its authentication.
A SIM Card

A SIM Card

  • Domestic:  The most frequently used smart card in domestic field is the DTH smart card. This card provides authorized access to the information coming from the satellites. In simple words the card with which we can get access to the Direct to Home TV services is nothing but a smart card. The information is encrypted and decrypted within a smart card.
A basic DTH System with the Smart Card


  • Ecommerce and Retail: Smart card can be used to store information like a person’s account details, the transaction details and can be used in purchasing goods online by acting as a credit card. Some retailers can also use smart cards to store points for a particular customer and provide necessary incentives to repeated customers.
  • Banking Application: The most prominent use of smart card in banking application is the replacement of the traditional magnetic stripe based credit or debit card. An example is the MasterCard and VISA.
VISA Smart Card

VISA Smart Card


  • Government Applications: Smart cards are being used by Government to issue identity cards to individual, which contains all the details of the individual. An example is the recently started Adhar card scheme in India.
Adhar Card Model

Adhar Card Model

  • Secured Physical access: Smart cards can be used by Organizations or differed public areas to provide authorized access to the employees (members of the organization) or other persons to the secured areas. The smart card generally contains identity details of the individual which is scanned and checked.


A Sample ID Card for Organizations

A Sample ID Card for Organizations


A Working Application of a Smart Card System to provide Authorized Access to Secured Areas

As seen, one of the prominent applications of a smart card is storing the identity of an individual. When the person tries to enter a secured area, the data in his/her smart card is checked with the available data in the database and if matched, the person is allowed access, else not.

A Smart Card System

A Smart Card System 


The system consists of 4 main parts:

  • A smart Card which is generally a contact memory smart card which contains the information about the individual.
  • A smart card reader which is generally a contact smart card reader and is used to read information from the card.
  • A controller which receives data from the smart card reader via the RS232 interface.
  • A load which is a relay in this case, used to drive a motor and connected to the controller via the relay driver IC.

The Working of the System is as follows:

Block Diagram showing a Smart Card System to allow Authorized Access

Block Diagram showing a Smart Card System to allow Authorized Access

  • The individual inserts his/her card in the card reader.
  • The card reader sends the data to the MAX 232 IC through the DB9 connector.
  • The Microcontroller receives the data from the MAX 232 and is accordingly programmed to compare the obtained information with the stored information in the database.
  • If the data matches, the Microcontroller develops logic high at its output pin, connected to the input pin of the relay driver.
  • The relay driver IC accordingly develops a low logic at its output and energizes the relay.
  • The common contact of the relay is now connected to the normally open contact and the motor connected in series with the relay contacts is rotated such that the door is opened.
  • In case the data doesn’t matches, the microcontroller is programmed to develop logic low at its output pin and the relay accordingly doesn’t get energized, keeping the door shut.
  • The obtained output is accordingly displayed on the LCD which shows whether the data is matched or not.
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