How are your details stored on an ATM card? Learn how the machine processes them.

The information visible on an ATM or debit card goes beyond just the card number, name, and expiry date.

ATM Card: In the world of online payments and technology, ATM cards have become an essential necessity, enabling people to withdraw or deposit money from their bank accounts at any ATM machine. However, a common question arises: how are user details stored on the card, and how does the machine process them upon insertion? Let’s understand the underlying technology.

What information is contained in an ATM card?

The information visible on an ATM or debit card is not limited to the card number, name, and expiry date. The card contains a chip or a magnetic strip that stores various types of data.

This data includes the card number, bank identification, card validity, security codes, and essential transaction-related information. However, the card does not store full details of your bank account or information regarding your current balance.

How do the chip and magnetic strip work?

Older ATM cards utilized a magnetic strip—a black band where data was recorded magnetically. When the card was swiped, the machine would read this strip to retrieve the details.

However, technology has advanced significantly. Modern ATM and debit cards now use EMV chips. These chips function like miniature computers, generating a unique security code for every transaction. Consequently, chip-enabled cards are considered more secure than older cards.

How does the ATM recognize the card?

When you insert your card into the ATM, the machine first scans the card's chip or magnetic strip. The information retrieved from the card is then transmitted to the bank's server.

The server verifies whether the card is valid, checks its active status, and confirms the existence of the associated bank account. After this, the machine prompts you to enter your PIN.

What happens after you enter the PIN?

Once the PIN is entered, the ATM encrypts the information and transmits it to the bank's server. The bank's system then verifies the PIN against its records.

If the PIN is found to be correct, the server authorizes the machine to proceed with the transaction. You can then perform essential tasks such as checking your balance or withdrawing cash.

Various security measures are employed.

Modern ATM cards utilize technologies such as encryption, EMV chips, PIN verification, and real-time server verification. These security measures help mitigate the risks of card cloning and fraud.