Credit Card PLease
"Credit Card" a status symbol for people specially in the developing countries.
A credit card is nothing, but a thin plastic card, usually 3-1/8 inches by 2-1/8 inches in size, that contains identification information such as a signature or picture, and authorizes the person named on it to charge purchases or services to his account -- charges for which he will be billed periodically. Today, the information on the card is read by automated teller machines (ATMs), store readers, and bank and Internet computers.
the use of credit cards originated in the United States during the 
1920s, when individual companies, such as hotel chains and oil companies, began issuing them to customers for purchases made at those businesses. This use increased significantly after World War II.
1920s, when individual companies, such as hotel chains and oil companies, began issuing them to customers for purchases made at those businesses. This use increased significantly after World War II.The first universal credit card -- one that could be used at a variety of stores and businesses -- was introduced by Diners Club, Inc., in 1950. With this system, the credit-card company charged cardholders an annual fee and billed them on a monthly or yearly basis. Another major universal card -- "Don't leave home without it!" -- was established in 1958 by the American Express company.
Later came the bank credit-card system. Under this plan, the bank credits the account of the merchant as sales slips are received (this means merchants are paid quickly -- something they love!) and assembles charges to be billed to the cardholder at the end of the billing period. The cardholder, in turn, pays the bank either the entire balance or in monthly installments with interest (sometimes called carrying charges).
The stripe on the back of a credit card is a magnetic stripe, often called a magstripe. The magstripe is made up of tiny iron-based magnetic particles in a plastic-like film. Each particle is really a tiny bar magnet about 20-millionths of an inch long.
After you or the cashier swipes your credit card through a reader, the EDC software at the point-of-sale (POS) terminal dials a stored telephone number (using a modem) to call an acquirer. An acquirer is an organization that collects credit-authentication requests from merchants and provides the merchants with a payment guarantee.
When the acquirer company gets the credit-card authentication request, it checks the transaction for validity and the record on the magstripe for:
Merchant ID
Valid card number
Expiration date
Credit-card limit
Card usage
Single dial-up transactions are processed at 1,200 to 2,400 bits per second (bps), while direct Internet attachment uses much higher speeds via this protocol. In this system, the cardholder enters a personal identification number (PIN) using a keypad.
The PIN is not on the card -- it is encrypted (hidden in code) in a database. (For example, before you get cash from an ATM, the ATM encrypts the PIN and sends it to the database to see if there is a match.) The PIN can be either in the bank's computers in an encrypted form (as a cipher) or encrypted on the card itself. The transformation used in this type of cryptography is called one-way. This means that it's easy to compute a cipher given the bank's key and the customer's PIN, but not computationally feasible to obtain the plain-text PIN from the cipher, even if the key is known. This feature was designed to protect the cardholder from being impersonated by someone who has access to the bank's computer files.
Likewise, the communications between the ATM and the bank's central computer are encrypted to prevent would-be thieves from tapping into the phone lines, recording the signals sent to the ATM to authorize the dispensing of cash and then feeding the same signals to the ATM to trick it into unauthorized dispensing of cash.
If this isn't enough protection to ease your mind, there are now cards that utilize even more security measures than your conventional credit card: Smart Cards.
The "smart" credit card is an innovative application that involves all aspects of cryptography (secret codes), not just the authentication we described in the last section. A smart card has a microprocessor built into the card itself. Cryptography is essential to the functioning of these cards in several ways:
The user must corroborate his identity to the card each time a transaction is made, in much the same way that a PIN is used with an ATM.
The card and the card reader execute a sequence of encrypted sign/countersign-like exchanges to verify that each is dealing with a legitimate counterpart.
Once this has been established, the transaction itself is carried out in encrypted form to prevent anyone, including the cardholder or the merchant whose card reader is involved, from "eavesdropping" on the exchange and later impersonating either party to defraud the system. This elaborate protocol is conducted in such a way that it is invisible to the user, except for the necessity of entering a PIN to begin the transaction.
Smart cards first saw general use in France in 1984. They are now hot commodities that are expected to replace the simple plastic cards most of us use now. Visa and MasterCard are leading the way in the United States with their smart card technologies.
The chips in these cards are capable of many kinds of transactions. For example, you could make purchases from your credit account, debit account or from a stored account value that's reloadable. The enhanced memory and processing capacity of the smart card is many times that of traditional magnetic-stripe cards and can accommodate several different applications on a single card. It can also hold identification information, keep track of your participation in an affinity (loyalty) program or provide access to your office. This means no more shuffling through cards in your wallet to find the right one -- the smart card will be the only one you need!
Experts say that internationally accepted smart cards will be increasingly available over the next several years. Many parts of the world already use them, but their reach is limited. The smart card will eventually be available to anyone who wants one, but for now, it's available mostly to those participating in special programs.
When the acquirer company gets the credit-card authentication request, it checks the transaction for validity and the record on the magstripe for:
Merchant ID
Valid card number
Expiration date
Credit-card limit
Card usage
Single dial-up transactions are processed at 1,200 to 2,400 bits per second (bps), while direct Internet attachment uses much higher speeds via this protocol. In this system, the cardholder enters a personal identification number (PIN) using a keypad.
The PIN is not on the card -- it is encrypted (hidden in code) in a database. (For example, before you get cash from an ATM, the ATM encrypts the PIN and sends it to the database to see if there is a match.) The PIN can be either in the bank's computers in an encrypted form (as a cipher) or encrypted on the card itself. The transformation used in this type of cryptography is called one-way. This means that it's easy to compute a cipher given the bank's key and the customer's PIN, but not computationally feasible to obtain the plain-text PIN from the cipher, even if the key is known. This feature was designed to protect the cardholder from being impersonated by someone who has access to the bank's computer files.
Likewise, the communications between the ATM and the bank's central computer are encrypted to prevent would-be thieves from tapping into the phone lines, recording the signals sent to the ATM to authorize the dispensing of cash and then feeding the same signals to the ATM to trick it into unauthorized dispensing of cash.
If this isn't enough protection to ease your mind, there are now cards that utilize even more security measures than your conventional credit card: Smart Cards.
The "smart" credit card is an innovative application that involves all aspects of cryptography (secret codes), not just the authentication we described in the last section. A smart card has a microprocessor built into the card itself. Cryptography is essential to the functioning of these cards in several ways:
The user must corroborate his identity to the card each time a transaction is made, in much the same way that a PIN is used with an ATM.
The card and the card reader execute a sequence of encrypted sign/countersign-like exchanges to verify that each is dealing with a legitimate counterpart.
Once this has been established, the transaction itself is carried out in encrypted form to prevent anyone, including the cardholder or the merchant whose card reader is involved, from "eavesdropping" on the exchange and later impersonating either party to defraud the system. This elaborate protocol is conducted in such a way that it is invisible to the user, except for the necessity of entering a PIN to begin the transaction.
Smart cards first saw general use in France in 1984. They are now hot commodities that are expected to replace the simple plastic cards most of us use now. Visa and MasterCard are leading the way in the United States with their smart card technologies.
The chips in these cards are capable of many kinds of transactions. For example, you could make purchases from your credit account, debit account or from a stored account value that's reloadable. The enhanced memory and processing capacity of the smart card is many times that of traditional magnetic-stripe cards and can accommodate several different applications on a single card. It can also hold identification information, keep track of your participation in an affinity (loyalty) program or provide access to your office. This means no more shuffling through cards in your wallet to find the right one -- the smart card will be the only one you need!
Experts say that internationally accepted smart cards will be increasingly available over the next several years. Many parts of the world already use them, but their reach is limited. The smart card will eventually be available to anyone who wants one, but for now, it's available mostly to those participating in special programs.
