Personal Identification Number

Personal Identification Number (PIN) is a numeric code used to authenticate the cardholder during payment transactions and ATM withdrawals. PINs are most commonly required for debit card transactions, both at ATMs and at point-of-sale terminals.

When making a purchase with a PIN, the cardholder enters their code on a keypad to verify their identity. This authentication adds a security layer beyond just possessing the physical card—even if a card is lost or stolen, it cannot be used without the correct PIN.

Once the PIN is verified, the transaction information is sent to the merchant acquiring bank, which manages settlement. Then, the processing network forwards the payment details to the issuing bank. The issuing bank performs security checks to prevent fraud and ensure funds are available.

After approval, the transaction flows back through the processor to the merchant acquiring bank, which notifies the merchant and completes the settlement process.

PINs are typically 4-6 digits and numeric only. For security, cardholders should avoid easily guessable combinations like birthdates, repeated numbers (1111), or sequential patterns (1234). A random PIN helps prevent unauthorized access if the card falls into the wrong hands.

Debit transactions usually require a PIN, while credit card transactions typically use a signature or no verification for contactless payments. Some regions and card networks support credit card PINs (common in Europe), which provide additional security compared to signature-based verification.