Kortinnumero

Kortinnumero is the unique numeric identifier printed on or stored with a card that is used to authorize transactions or grant access to services. It commonly refers to the number on payment cards such as credit and debit cards, but it can also apply to other types of cards like transit passes or membership cards. The term is used in many languages to describe the primary identifier that links the physical card to the issuing account.

In payment cards, the kortinnumero typically consists of 13 to 19 digits. The first six digits form the issuer identification number (IIN), also known as the BIN, which identifies the card network and the issuing bank. The digits in the middle identify the individual account, and the final digit is a check digit used to validate the number via the Luhn algorithm. The exact length and arrangement can vary by card scheme and issuer, but the general structure supports quick validation and routing in electronic payments.

Usage of the kortinnumero occurs in card-present and card-not-present transactions. In stores, the number is read from the card or entered into a payment terminal. Online purchases require entering the card number into a secure form, often alongside an expiration date and a security code. In digital wallets, the actual card number is often replaced by a token to reduce exposure.

Security and privacy are critical: the full nummer should be protected and only shared with trusted payment processors. Merchants follow standards such as PCI DSS, and practices like masking the number on displays and using tokenization help minimize risk of misuse.